Processes for the preparation of benzotriazole UV absorbers

ABSTRACT

Provided is a process for preparing 2H-benzotriazole UV absorbers containing a perfluoroalkyl moiety at the 5-position of the benzo ring, for example a trifluoromethyl group, which involves diazotizing the perfluoroalkyl substituted o-nitroaniline using concentrated sulfuric acid plus sodium nitrite or nitrosylsulfuric acid to form the corresponding monoazobenzene intermediate via the diazonium salt intermediate which is reduced to the corresponding 5-perfluoroalkyl substituted 2H-benzotriazole UV absorber compound by conventional reduction means. Also provided is a novel one-pot, multiphase reaction for the preparation of 2(2-nitrophenylazo) substituted phenols, which are precursors for 2H-benzotriazole UV absorbers.

[0001] This is a continuation-in-part of application No. 09/632,217,filed Aug. 3, 2000.

[0002] The instant invention pertains to a superior process for making2H-benzotriazole UV absorbers which are substituted by a perfluoroalkylgroup, i.e. trifluoromethyl, usually at the 5-position of the benzoring; and to a novel process for the preparation of the intermediate2-(2-nitophenylazo) phenols.

BACKGROUND OF THE INVENTION

[0003] Japanese TOKU-KAI-Hei 3-57690 generically discloses compoundswhere the benzo ring of the benzotriazole may be substituted by a hostof groups including hydrogen, alkyl, alkoxy, aryloxy, halogen,substituted amino, cyano, nitro, acyl and trihalomethyl. The onlyspecific benzotriazole compounds mentioned are those where the benzoring is unsubstituted or is substituted at the 5-position by a chlorogroup. There is no evidence that the Japanese inventors made anytrihalomethyl substituted benzotriazole.

[0004] German Patent Application 116,230 describes inter alia thepreparation of5-trifluoromethyl-2-(2-hydroxy-5-methylphenyl)-2H-benzotriazolyl-1-oxide.The only synthesis conditions disclosed for the entire group ofcompounds prepared show the diazotization of the appropriateo-nitroaniline with aqueous sodium nitrite and hydrochloric acid. TheGerman workers offer no synthetic details or more importantly no yieldinformation for the preparation of5-trifluoromethyl-2-(2-hydroxy-5-methylphenyl)-2H-benzotriazolyl-1-oxide.

[0005] In British Patent Application 2,319,035 and U.S. Pat. No.5,977,219, all benzotriazole compounds containing a trifluoromethylmoiety at the 5-position of the benzo ring are referenced to thesynthetic procedure of Example 1. Issues to be considered with thissynthetic procedure are (a) a 100% excess of the diazonium salt relativeto phenol is used; (b) the monoazo prepared by this method is describedas a paste (generally materials with the consistency of a paste areimpure); the pure monoazo is a solid with a melting point of 101-105°C.; (c) the yield of benzotriazole based on the phenol is 11% and isonly 5.5% based on the CF₃-substituted o-nitroaniline; (d) thediazotization preparation in Example 1 uses concentrated hydrochloricacid; (e) a paper in the J. Org. Chemistry, 1985, (50) 3612 indicatesthat the reaction of 4-trifluoromethyl-2-nitroaniline with hydrochloricacid can lead to the formation of 4-trifluoromethyl-2-chloroaniline.Such a reaction could at least partly account for the low yields seenwith the use of concentrated hydrochloric acid in the diazotizationstep.

[0006] The following references describe one-pot processes for makingazo compounds:

[0007] U.S. Pat. No. 2,418,416 describes a process for manufacturinglakes of azo compounds. The process involves dissolving the diazotizableamine and coupling component in an acidic, aqueous solution. The aminewas diazotized by addition of the nitrosating reagent to the acidic,aqueous solution. After diazotization was complete, the pH of thesolution was raised by addition of base to ca. 7.8.

[0008] U.S. Pat. No. 2,478,767 also describes a process formanufacturing lakes of azo compounds. The diazotizable amine isdissolved in an acidic, aqueous solution and heated to 100° F. Thecoupling component and nitrosating reagent are dissolved in a basic,aqueous solution that is heated to 150° F. The two solutions are mixedtogether controlling the pH of the mixture in the range of 6-7.2.

[0009] U.S. Pat. No. 2,478,768 also describes a process formanufacturing lakes of azo compounds. The process involves adding anacidic, aqueous solution containing a soluble salt of the laking agentto a basic, aqueous solution containing the diazotizable amine, couplingcomponent and nitrosating reagent. The final pH of the reaction mass is6-7.2.

[0010] U.S. Pat. No. 3,793,305 describes a one-step process for thepreparation of azo dyes by simultaneously contacting and reacting adiazotizable amine, an active methylene coupling component and adiazotizing agent in an acidic, aqueous solution. The invention requiresthat the reaction media must be able to dissolve a portion of both thediazotizable amine and the coupling component. The active methylenecoupling components named are: b-diketones, b-keto esters, b-ketoamides, b-keto nitriles, anilides of cyanoacetic acid, heterocyclicb-keto amides and b-imino amides.

[0011] U.S. Pat. No. 4,035,350 describes a process for the preparationof azo dyes where the diazotizable amine and the coupling component areboth in solution and the diazotizing agent is added. The inventionrequires that either the amine or coupling component contain an acidgroup. The invention also claims the use of polar aprotic solvents thatare miscible with water.

[0012] Hashida, Y. et. al. reported in “Phase Transfer-Catalyzed AzoCoupling Reaction in Two Phase Systems”, Bull. Chem. Soc. Jpn. 61,905-909 (1988) the phase transfer catalyzed azo coupling reaction in atwo phase system. This paper describes the coupling reaction betweenp-methoxybenzenediazonium tetrafluoroborate with N,N-dimethylaniline ina biphasic water-1,2-dichloroethane system with various phase transfercatalysts.

[0013] Tamagaki, S. et. al. reported in Chemistry Letters, pp.1237-1240(1982) for the Chemical Society of Japan that silica gel facilitated azocoupling reactions between p-nitrobenzenediazonium tetrafluoroborate andaromatic amines. This process involves a solid-solid-liquid multiphasemixture via a solid-liquid interfacial azo-coupling reaction.

[0014] In March, J, “Advanced Organic Chemistry,” Fourth Ed., New York,pages 522-523, it is pointed out that it is well known that activesubstrates such as phenols are readily nitrated under standardnitrosation conditions.

OBJECTS OF THE INVENTION

[0015] An object of the invention is to provide a facile and improvedprocess for the preparation of 5-perfluoroalkyl substituted2H-benzotriazole UV absorbers.

[0016] Another object of the invention is to provide a novel one-potprocess for the preparation of 2-(2-nitrophenylazo) phenols, referred toin this application as monoazobenzene intermediates. Thesemonoazobenzene intermediates are useful for the preparation ofhydroxyphenyl benzotriazole UV absorbers.

DETAILED DISCLOSURE Preparation of 5-Perfluoroalkyl Substituted2H-Benzotriazoles

[0017] The instant invention describes an improved process for thepreparation of 5-perfluoroalkyl (for example trifluoromethyl)substituted 2H-benzotriazoles where in the diazotization step aqueousalkali metal (for instance sodium) nitrite and concentrated hydrochloricacid are replaced by aqueous alkali metal (for instance sodium) nitriteand concentrated sulfuric acid; and where aqueous alkali metal (sodium)nitrite and concentrated sulfuric acid are replaced with anhydrousnitrosylsulfuric acid with concentrated sulfuric acid as a diluent toallow operation at safe concentrations.

[0018] The instant invention more specifically pertains to a process forpreparing a compound of formula (I)

[0019] which process comprises

[0020] diazotizing a perfluoroalkyl substituted o-nitroaniline offormula (II)

[0021]  using concentrated sulfuric acid and an alkali metal nitrite(for instance sodium nitrite) or nitrosylsulfuric acid to form thecorresponding diazonium salt of formula (III)

[0022] coupling said diazonium salt with a phenol of formula (IV)

[0023] to form a monoazobenzene compound of formula (V)

[0024] reducing the monoazobenzene intermediate of formula (V) to thecorresponding 2H-benzotriazole compound of formula (I) by conventionalreduction means;

[0025] wherein

[0026] G₁ is hydrogen or chloro,

[0027] G₂ is perfluoroalkyl of 1 to 12 carbon atoms,

[0028] E₁ is hydrogen, straight or branched chain alkyl of 1 to 24carbon atoms, straight or branched chain alkenyl of 2 to 24 carbonatoms, cycloalkyl of 5 to 12 carbon atoms, phenylalkyl of 7 to 15 carbonatoms, phenyl, or said phenyl or said phenylalkyl substituted on thephenyl ring by one to three alkyl of 1 to 4 carbon atoms; or E₁ is alkylof 1 to 24 carbon atoms substituted by one or two hydroxy groups,

[0029] E₂ is straight or branched alkyl chain of 1 to 24 carbon atoms,straight or branched chain alkenyl of 2 to 18 carbon atoms, cycloalkylof 5 to 12 carbon atoms, phenylalkyl of 7 to 15 carbon atoms, phenyl, orsaid phenyl or said phenylalkyl substituted on the phenyl ring by one tothree alkyl of 1 to 4 carbon atoms; or E₂ is said alkyl of 1 to 24carbon atoms or said alkenyl of 2 to 18 carbon atoms substituted by oneor more —OH, —OCOE₁₁, —OE₄, —NCO, —NHCOE₁₁, or —NE₇E₈, or mixturesthereof, where E₄ is straight or branched chain alkyl of 1 to 24 carbonatoms; alkenyl of 2 to 18 carbon atoms; or said alkyl or said alkenylinterrupted by one or more —O—, —NH— or —NE₄-groups or mixtures thereofand which can be unsubstituted or substituted by one or more —OH, —OE₄or —NH₂ groups or mixtures thereof; or E₂ is —(CH₂)_(m)—CO—E₅;

[0030] E₅ is OE₆ or NE₇E₈, or

[0031] E₅ is —PO(OE₁₂)₂, —OSi(E₁₁)₃ or —OCO—E₁₁, or straight or branchedchain C₁-C₂₄alkyl which can be interrupted by —O—, —S— or —NE₁₁, andwhich can be unsubstituted or substituted by —OH or —OCO—E₁₁, C₅-C₁₂cycloalkyl which is unsubstituted or substituted by —OH, straight chainor branched C₂-C₁₈alkenyl which is unsubstituted or substituted by —OH,C₇-C₁₅aralkyl, —CH₂—CHOH—E₁₃ or glycidyl,

[0032] E₆ is hydrogen, straight or branched chain C₁-C₂₄alkyl which isunsubstituted or substituted by one or more OH, OE₄ or NH₂ groups, or—OE₆ is —(OCH₂CH₂)_(w)OH or —(OCH₂CH₂)_(w)OE₂₁where w is 1 to 12 and E₂₁is alkyl of 1 to 12 carbon atoms,

[0033] E₇ and E₈ are independently hydrogen, alkyl of 1 to 18 carbonatoms, straight or branched chain alkenyl of 2 to 18 carbon atoms,straight or branched chain C₃-C₁₈alkyl which is interrupted by —O—, —S—or —NE₁₁—, C₅-C₁₂cycloalkyl, C₆-C₁₄aryl or C₁-C₃hydroxylalkyl, or E₇ andE₈ together with the N atom are a pyrrolidine, piperidine, piperazine ormorpholine ring, or

[0034] E₅ is —X—(Z)_(p)—Y—E₁₅ wherein

[0035] X is —O— or —N(E₁₆)—,

[0036] Y is —O— or —N(E₁₇)—,

[0037] Z is C₂-C₁₂-alkylene, C₄-C₁₂-alkylene interrupted by one to threenitrogen atoms, oxygen atoms or a mixture thereof, or isC₃-C₁₂-alkylene, butenylene, butynylene, cyclohexylene or phenylene,each substituted by a hydroxyl group,

[0038] m is zero, 1 or 2,

[0039] p is 1, or p is also zero when X and Y are —N(E₁₆)— and —N(E₁₇)—,respectively,

[0040] E₁₅ is a group —CO—C(E₁₈)═C(H)E₁₉ or, when Y is —N(E₁₇)—, formstogether with E₁₇ a group —CO—CH═CH—CO—, wherein E₁₈ is hydrogen ormethyl, and E₁₉ is hydrogen, methyl or —CO—X—E₂₀, wherein E₂₀ ishydrogen, C₁-C₁₂-alkyl or a group of the formula

[0041] wherein the symbols E₁, G₂, X, Z, m and p have the meaningsdefined above, and E₁₆ and E₁₇ independently of one another arehydrogen, C₁-C₁₂-alkyl, C₃-C₁₂-alkyl interrupted by 1 to 3 oxygen atoms,or is cyclohexyl or C₇-C₁₅aralkyl, and E₁₆ together with E₁₇ in the casewhere Z is ethylene, also forms ethylene,

[0042] E₁₁ is hydrogen, straight or branched chain C₁-C₁₈alkyl,C₅-C₁₂cycloalkyl, straight or branched chain C₂-C₁₈alkenyl, C₆-C₁₄arylor C₇-C₁₅aralkyl,

[0043] E₁₂ is straight or branched chain C₁-C₁₈alkyl, straight orbranched chain C₃-C₁₈alkenyl, C₅-C₁₀cycloalkyl, C₆-C₁₆aryl orC₇-C₁₅aralkyl, and

[0044] E₁₃ is H, straight chain or branched C₁-C₁₈alkyl which issubstituted by —PO(OE₁₂)₂, phenyl which is unsubstituted or substitutedby OH, C₇-C₁₅aralkyl or —CH₂OE₁₂,

[0045] with the proviso that when concentrated sulfuric acid and alkalimetal nitrite are used, E₁ and E₂ are alkyl of 1 to 4 carbon atoms; orE₁ can also be hydrogen.

[0046] In the above-described process, it is contemplated that the groupG₂ may also be phenyl, naphthyl, biphenylyl or 9-phenanthryl substitutedby electron-withdrawing groups as described in co-pending applicationNo. 09/722,876, filed Nov. 27, 2000. For example, G₂ may be phenylfurther substituted by perfluoroalkyl of 1 to 12 carbon atoms. Thedisclosure of application No. 09/722,876 is hereby incorporated byreference.

[0047] For example, the instant process involves the preparation of acompound of formula (Ia)

[0048] which process comprises

[0049] diazotizing a substituted o-nitroaniline compound of formula(IIa)

[0050]  using concentrated sulfuric acid and sodium nitrite ornitrosylsulfuric acid to form the diazonium salt of formula (IIIa)

[0051] coupling said diazonium salt with a phenol of formula (IVa)

[0052]  to form the corresponding monoazobenzene compound of formula(Va)

[0053] reducing the monoazobenzene intermediate of formula (Va) to thecorresponding 2H-benzotriazole compound of formula (Ia) by conventionalreduction means;

[0054] with the proviso that when concentrated sulfuric acid and alkalimetal nitrite are used, E₁ and E₂ are alkyl of 1 to 4 carbon atoms; orE₁ can also be hydrogen.

[0055] For example, in the compound of formula (I),

[0056] G₁ is hydrogen,

[0057] G₂ is —CF₃,

[0058] E₁ is phenylalkyl of 7 to 15 carbon atoms, phenyl, or said phenylor said phenylalkyl substituted on the phenyl ring by one to three alkylof 1 to 4 carbon atoms,

[0059] E₂ is straight or branched alkyl chain of 1 to 24 carbon atoms,straight or branched chain alkenyl of 2 to 18 carbon atoms, cycloalkylof 5 to 12 carbon atoms, phenylalkyl of 7 to 15 carbon atoms, phenyl, orsaid phenyl or said phenylalkyl substituted on the phenyl ring by one tothree alkyl of 1 to 4 carbon atoms; or E₂ is said alkyl of 1 to 24carbon atoms or said alkenyl of 2 to 18 carbon atoms substituted by oneor more —OH, —OCOE₁₁, —OE₄, —NCO, —NH₂, —NHCOE₁₁, —NHE₄ or —N(E₄)₂, ormixtures thereof, where E₄ is straight or branched chain alkyl of 1 to24 carbon atoms; or said alkyl or said alkenyl interrupted by one ormore —O—, —NH— or —NE₄— groups or mixtures thereof and which can beunsubstituted or substituted by one or more —OH, —OE₄ or —NH₂ groups ormixtures thereof; or is a compound of formula (I) wherein,

[0060] G₁ is hydrogen,

[0061] G₂ is —CF₃,

[0062] E₁ is hydrogen or straight or branched alkyl of 4 to 24 carbonatoms, and

[0063] E₂ is as defined above.

[0064] For example, the compound of formula (I) is also where

[0065] G₁ is hydrogen,

[0066] G₂ is —CF₃,

[0067] E₁ is hydrogen, straight or branched alkyl of 4 to 24 carbonatoms or phenylalkyl of 7 to 15 carbon atoms,

[0068] E₂ is —(CH₂)_(m)—CO—E₅,

[0069] E₅ is —OE₆ or —NE₇E₈, or

[0070] E₅ is —X—(Z)_(p)—Y—E₁₅

[0071] wherein

[0072] X is —O— or —N(E₁₆)—,

[0073] Y is —O— or —N(E₁₇)—,

[0074] Z is C₂-C₁₂-alkylene, C₄-C₁₂-alkylene interrupted by one to threenitrogen atoms, oxygen atoms or a mixture thereof, or isC₃-C₁₂-alkylene, butenylene, butynylene, cyclohexylene or phenylene,each substituted by a hydroxyl group,

[0075] m is 0, 1, 2 or 3,

[0076] p is 1, or p is also zero when X and Y are —N(E₁₆)— and —N(E₁₇)—,respectively,

[0077] E₁₅ is a group —CO—C(E₁₈)═C(H)E₁₉ or, when Y is —N(E₁₇)—, formstogether with E₁₇ a group —CO—CH═CH—CO—, wherein E₁₈ is hydrogen ormethyl, and E₁₉ is hydrogen, methyl or —CO—X—E₂₀, wherein E₂₀ ishydrogen, C₁-C₁₂-alkyl or a group of the formula

[0078] For instance, the compound of formula (I) is where

[0079] G₁ is hydrogen,

[0080] G₂ is —CF₃,

[0081] E₁ is phenylalkyl of 7 to 15 carbon atoms, phenyl, or said phenylor said phenylalkyl substituted on the phenyl ring by one to three alkylof 1 to 4 carbon atoms,

[0082] E₂ is straight or branched alkyl chain of 1 to 24 carbon atoms,straight or branched chain alkenyl of 2 to 18 carbon atoms, cycloalkylof 5 to 12 carbon atoms, phenylalkyl of 7 to 15 carbon atoms, phenyl, orsaid phenyl or said phenylalkyl substituted on the phenyl ring by one tothree alkyl of 1 to 4 carbon atoms; or E₂ is said alkyl of 1 to 24carbon atoms or said alkenyl of 2 to 18 carbon atoms substituted by oneor more —OH, —OCOE₁₁, —NH₂ or —NHCOE₁₁, or mixtures thereof, or saidalkyl or said alkenyl interrupted by one or more —O— and which can beunsubstituted or substituted by one or more —OH; or is a compound offormula (I) wherein,

[0083] G₁ is hydrogen,

[0084] G₂ is —CF₃,

[0085] E₁ is hydrogen, straight or branched alkyl of 4 to 24 carbonatoms or phenylalkyl of 7 to 15 carbon atoms, and

[0086] E₂ is as defined above.

[0087] For instance, the compound of formula (I) is where

[0088] G₁ is hydrogen,

[0089] G₂ is —CF₃,

[0090] E₁ is hydrogen, straight or branched alkyl of 4 to 24 carbonatoms or phenylalkyl of 7 to 15 carbon atoms,

[0091] E₂ is —(CH₂)_(m)—CO—E₅,

[0092] E₅ is —OE₆ or —NE₇E₈ where

[0093] E₆ is hydrogen, straight or branched chain C₁-C₂₄alkyl which isunsubstituted or substituted by one or more OH groups, or —OE₀ is—(OCH₂CH₂)_(w)OH or —(OCH₂CH₂)_(w)OE₂₁ where w is 1 to 12 and E₂₁ isalkyl of 1 to 12 carbon atoms, and

[0094] E₇ and E₈ are independently hydrogen, alkyl of 1 to 18 carbonatoms, straight or branched chain C₃-C₁₈alkyl which is interrupted by—O—, —S— or —NE₁₁—, C₅-C₁₂cycloalkyl, C₆-C₁₄aryl or C₁-C₃hydroxylalkyl,or E₇ and E₈ together with the N atom are a pyrrolidine, piperidine,piperazine or morpholine ring.

[0095] Illustrative of the compounds of formula (I) which can be made bythe instant process are

[0096] (a)5-trifluoromethyl-2-(2-hydroxy-3-α-cumyl-5-tert-octylphenyl)-2H-benzotriazole;

[0097] (b)5-trifluoromethyl-2-(2-hydroxy-5-tert-octylphenyl)-2H-benzotriazole;

[0098] (c)5-trifluoromethyl-2-(2-hydroxy-3,5-di-tert-octylphenyl)-2H-benzotriazole;

[0099] (d)5-trifluoromethyl-2-[2-hydroxy-5-(2-hydroxyethyl)phenyl]-2H-benzotriazole;

[0100] (e)5-trifluoromethyl-2-(2-hydroxy-3,5-di-α-cumylphenyl)-2H-benzotriazole;

[0101] (f)3-(5-trifluromethyl-2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyhydrocinnamicacid;

[0102] (g) methyl3-(5-trifluoromethyl-2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyhydrocinnamate;

[0103] (h) isooctyl3-(5-trifluoromethyl-2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyhydrocinnamate;

[0104] (i)5-trifluoromethyl-2-[2-hydroxy-5-(3-hydroxypropyl)phenyl]-2H-benzotriazole;

[0105] (j)5-trifluoromethyl-2-[2-hydroxy-5-(3-acryloyloxypropyl)phenyl]-2H-benzotriazole;

[0106] (k)5-trifluoromethyl-2-[2-hydroxy-5-(3-methacryloyloxypropyl)phenyl]-2H-benzotriazole;

[0107] (l)5-trifluoromethyl-2-[2-hydroxy-5-(3-acrylylaminopropyl)phenyl]-2H-benzotriazole;

[0108] (m)5-trifluoromethyl-2-[2-hydroxy-5-(3-methacrylylaminopropyl)phenyl]-2H-benzotriazole;

[0109] (n)5-trifluoromethyl-2-(2-hydroxy-3-α-cumyl-5-tert-butylphenyl)-2H-benzotriazole;

[0110] (o)5-trifluoromethyl-2-(2-hydroxy-3-α-cumyl-5-nonylphenyl)-2H-benzotriazole;

[0111] (p)5-trifluoromethyl-2-[2-hydroxy-3-α-cumyl-5-(2-hydroxyethyl)phenyl]-2H-benzotriazole;

[0112] (q)5-trifluoromethyl-2-[2-hydroxy-3-α-cumyl-5-(3-hydroxypropyl)phenyl]-2H-benzotriazole;

[0113] (r)5-trifluoromethyl-2-(2-hydroxy-3,5-ditert-amylphenyl)-2H-benzotriazole;

[0114] (s)5-trifluoromethyl-2-(2-hydroxy-3,5-ditert-butylphenyl)-2H-benzotriazole;

[0115] (t)5-trifluoromethyl-2-(2-hydroxy-3-dodecyl-5-methylphenyl)-2H-benzotriazole;

[0116] (u)5-trifluoromethyl-2-[2-hydroxy-3-tert-butyl-5-(3-hydroxypropyl)phenyl)-2H-benzotriazole;and

[0117] (v)5-trifluoromethyl-2-[2-hydroxy-3-tert-butyl-5-(2-hydroxyethyl)phenyl]-2H-benzotriazole;

[0118] For example, the instant process involves the preparation of acompound of formula (Ib),

[0119] which process comprises

[0120] diazotizing a substituted o-nitroaniline compound of formula(IIa)

[0121]  using nitrosylsulfuric acid to form the diazonium salt offormula (IIIa)

[0122] coupling said diazonium salt with a phenol of formula (IVb)

[0123]  to form the corresponding monoazobenzene compound of formula(Vb)

[0124] reducing the monoazobenzene intermediate of formula (Vb) to thecorresponding 2H-benzotriazole compound of formula (Ib) by conventionalreduction means.

[0125] For instance, the instant process involves the preparation of acompound of formula (Ic),

[0126] which process comprises

[0127] diazotizing a substituted o-nitroaniline compound of formula(IIa)

[0128]  using nitrosylsulfuric acid to form the diazonium salt offormula (IIIa)

[0129] coupling said diazonium salt with a phenol of formula (IVc)

[0130]  to form the corresponding monoazobenzene compound of formula(Vc)

[0131] reducing the monoazobenzene intermediate of formula (Vc) to thecorresponding 2H-benzotriazole compound of formula (Ic) by conventionalreduction means.

[0132] Ia. In the process for making the diazonium salts using aperfluoroalkyl substituted o-nitroaniline (i.e.4-trifluoromethyl-2-nitroaniline, CF₃—ONA), sulfuric acid and an aqueousalkali metal nitrite (i.e. sodium nitrite) solution, the followingprocess parameters pertain:

[0133] a. The molar ratio of CF₃—ONA:sulfuric acid is 1:10 to 1:1; forexample 1:5 to 1:1; for instance 1:2-3.5.

[0134] b. The molar ratio of CF₃—ONA:sodium nitrite is 1:1 to 1:4; forexample 1:1 to 1:2; for instance 1:1.

[0135] c. The temperature used for this reaction is from −30° C. to 50°C.; for example from −20° C. to 20° C.; for instance from −10° C. to 5°C.

[0136] Ib. In the process for making the diazonium salts using aperfluoroalkyl substituted o-nitroaniline (i.e.4-trifluoromethyl-2-nitroaniline, CF₃—ONA) and nitrosylsulfuric acid insulfuric acid, the following process parameters pertain:

[0137] a. The molar ratio of CF₃—ONA:nitrosylsulfuric acid is 1:1 to1:2; for example 1:1 to 1:1.2; for instance 1:1.

[0138] b. The molar ratio of CF₃—ONA:sulfuric acid is 1:1 to 1:10; forexample 1:2 to 1:7; for instance 1:2 to 1:5.

[0139] c. The temperature used for this reaction is from −30° C. to 50°C.; for example from −20° C. to 40° C.; for instance from 0° C. to 25°C.

[0140] When preparing a diazonium salt using nitrosylsulfuric acid, avery low amount of water is required. The system is essentiallyanhydrous. When sulfuric acid concentrations are under 90%,nitrosylsulfuric acid becomes nitric oxide (NO) and evolves as a gasbefore it has time to react with the CF₃—ONA. At the end of thediazotization reaction, the diazonium salt solution in sulfuric acid isdiluted with water to about 20-25%.

[0141] II. For the preparation of the monoazobenzene intermediate, thereare two different coupling methods possible. The alkaline couplingmethod is described in detail in U.S. Pat. Nos. 4,275,004 and 4,347,180which are incorporated herein by reference.

[0142] The acidic coupling process is described in detail in U.S. Pat.No. 5,436,322 which is incorporated herein by reference.

[0143] It is noted that instant Example 9 shows a coupling method whichneither strongly alkaline nor strongly acidic. Rather, this Exampleshows coupling which is buffered with acetic acid and sodium hydroxide.

[0144] The details of the present specific acidic coupling method aredescribed infra.

[0145] The diazonium salt formed as described above is reacted with theappropriate phenol in a solvent containing a surface active modifier ata temperature of −30° C. to 75° C.; for example at −20° C. to 50° C.;for instance at −10° C. to 35° C.

[0146] The solvents used are water, an aromatic hydrocarbon, analiphatic hydrocarbon or a mixture thereof. For instance, the solvent iswater, toluene, o-xylene, m-xylene, p-xylene or a mixture of saidxylenes, mesitylene, pseudocumene, hexane, heptane, octane, nonane or amixture thereof. For example, the solvent is water, toluene, o-xylene,m-xylene, p-xylene, a mixture of said xylenes, heptane or a mixturethereof.

[0147] The amount of solvent to be used is that sufficient to dissolvethe reactants. The amount of solvent is not critical, but making thesolution too dilute is to be avoided.

[0148] The surface active modifier to be used is any one or a mixture ofmaterials selected from the group consisting of emulsifying agents,surfactants, phase transfer agents and dispersants.

[0149] For instance, the surface active modifier is HOSTAPUR® SAS93(Hoechst) or PETROSUL® M-60 (Penreco). The amount used is that needed toensure adequate mixing of the reactants.

[0150] The molar ratio of diazonium salt:phenol is 2:1 to 1:2; forexample 1.5:1 to 1:1.5; for instance 1:1.

[0151] III. The monoazobenzene compounds prepared in the instant processcan be conveniently reduced to the corresponding benzotriazolyl-1 -oxideand then to the corresponding 2H-benzotriazole by any number ofconventional reduction methods. An illustrative list of such methods isgiven below, but should not be construed as being the only methodspossible for carrying out said reduction.

[0152] 1. EP 0380840 A1 describes the hydrogenation of abenzotriazolyl-1-oxide to the benzotriazole using palladium/carboncatalyst in toluene/water and in the presence of dimethylamine.

[0153] 2. EP 0380840 A1 also discloses the hydrogenation of abenzotriazolyl-1-oxide to the benzotriazole using Raney nickel catalystin toluene/2-butanol and in the presence of1,5-diazabicyclo[5.4.0]undecane.

[0154] 3. EP 0380839 A1 discloses the hydrogenation of anitromonoazobenzene to the benzotriazole using Raney nickel catalyst intoluene/isopropanol and in the presence of sodium hydroxide.

[0155] 4. EP 0380839 A1 also discloses the hydrogenation of anitromonoazobenzene to the benzotriazole using palladium/carbon catalystin toluene/water/isopropanol and in the presence of dimethylamine.

[0156] 5. Japanese Sho 37-5934 (1962) and U.S. Pat. No. 3,773,751describe the reduction of a nitromonoazobenzene to the benzotriazoleusing zinc, sodium hydroxide in an alcohol.

[0157] 6. U.S. Pat. No. 2,362,988 discloses a variety of methods for thereduction of a nitromonoazobenzene to a benzotriazole. These include theuse of:

[0158] a. ammonium sulfide;

[0159] b. an alkali metal sulfide;

[0160] c. zinc and ammonia;

[0161] d. hydrogen sulfide and sodium; or

[0162] e. zinc and hydrochloric acid.

[0163] 7. Japanese Sho 56-133076 (1981) describes the reduction of anitromonoazobenzene to a benzotriazole using quinone plus a variety ofcoreactants. These include:

[0164] a. zinc;

[0165] b. ammonium sulfide;

[0166] c. alkali metal sulfide;

[0167] d. alkali metal hydrosulfide; or

[0168] e. hydrazine.

[0169] 8. Japanese Sho 52-113973 (1977) and Sho 52-113974 (1977)describe the hydrogenation of a nitromonoazobenzene to a benzotriazoleusing a precious metal catalyst in the presence of a base.

[0170] 9. Japanese Sho 59-170172 (1984) and Sho 63-72682 (1988) describethe reduction of a nitromonoazobenzene to a benzotriazole using aquinone or an aromatic ketone in the presence of an alcohol and a baseand with heating.

[0171] 10. Japanese Sho 61-215378 (1986) describes the reduction of anitromonoazobenzene or a benzotriazolyl-1-oxide benzotriazole to abenzotriazole using an aldehyde and aromatic ketone in the presence of abase.

[0172] 11. Japanese Sho 63-72683 (1988) and U.S. Pat. No. 4,780,541describe the reduction of a nitromonoazobenzene or abenzotriazolyl-1-oxide benzotriazole to a benzotriazole using a primaryor secondary alcohol and an aromatic ketone in the presence of a base.

[0173] 12. Japanese Sho 63-186886 (1988) describes the electrolyticreduction of a nitromonoazobenzene or a benzotriazolyl-1-oxidebenzotriazole to a benzotriazole using an alkali metal hydroxide inwater or an aqueous alcohol solution.

[0174] 13. Japanese Sho 61-215379 (1986) and U.S. Pat. No. 4,789,541describe the reduction of a benzotriazolyl-1 -oxide benzotriazole to abenzotriazole using an aldehyde and an aromatic ketone in the presenceof a base.

[0175] 14. U.S. Pat. No. 5,571,924 describes the reduction of anitromonoazobenzene or a benzotriazolyl-1-oxide benzotriazole to abenzotriazole using hydrazine and a precious metal catalyst.

[0176] 15. U.S. Pat. No. 3,978,074 discloses the reduction of anitromonoazobenzene to a benzotriazole using a hydrogen and a noblemetal catalyst in the presence of an aqueous alkali metal hydroxidesolution.

[0177] 16. U.S. Pat. No. 4,219,480 discloses the reduction of anitromonoazobenzene to a benzotriazole using a hydrogen and a Raneynickel catalyst in the presence of an aqueous alkali metal hydroxidesolution or in the presence of an aliphatic amine.

[0178] 17. U.S. Pat. No. 4,230,867 discloses the reduction of anitromonoazobenzene to a benzotriazole using a hydrogen and a noblemetal catalyst in the presence of an aliphatic amine.

[0179] One-pot Process for the Preparation of 2-(2-Nitrophenylazo)Phenols

[0180] The present invention also provides a facile and improvedmultiphase process for the preparation of 2-(2-nitrophenylazo)substituted phenols and corresponding benzotriazole UV absorbers. Theinstant one-pot process is a highly efficient and environmentallyacceptable (“Green Chemistry: Theory and Practice” by P. T. Anastas andJ. C. Warner, Oxford press, 1998) in that: 1) The process can be carriedout using environmentally friendly solvents (water, hydrocarbons, etc.);2) The amount of corrosive, mineral acid required is low, decreasingwaste handling issues and the formation of hazardous by-products; 3) Italso offers safety advantages in that the diazonium salt is not isolatedor processed in any way. The intermediate diazonium salt is generated insitu and reacted immediately, keeping diazonium concentrations to aminimum thereby minimizing the risk of explosion, worker exposure orrelease to the environment. For reagents containing fluorinated groups,the risk of generation and release of hazardous HF is eliminated; 4) Theless stringent conditions produce fewer by-products resulting in higheryield and better product quality; 5) The process utilizes a singlevessel eliminating the risk of transferring hazardous materials from onevessel to another; and 6) Cycle time is decreased resulting in betterenergy efficiency.

[0181] It is very surprising that the single vessel, simultaneousdiazotization-coupling reaction works so well given that phenols arereadily oxidized and nitrated under the same reaction conditions. Seefor example March, J, “Advanced Organic Chemistry,” Fourth Ed., NewYork, pages 522-523.

[0182] Specifically, the instant one-pot process allows for theefficient preparation of a new class of benzotriazole ultraviolet lightabsorbers (UVA's), that is benzotriazole UVA's substituted in the 5position of the benzo ring with a —CF₃ group. Further, surprisingly, thepresent process may be applied to the preparation of2-(2-nitrophenylazo) substituted phenol (monoazo) intermediates ofpreviously known commercial benzotriazole UVA's, that is benzotriazoleUVA's with weaker electron withdrawing groups in the benzo ring (such aschloro) or benzotriazole UVA's with no electron withdrawing groups inthe benzo ring. The environmental and safety benefits of the instantprocess are also realized in the preparation of these currentlycommercially available benzotriazoles.

[0183] Specifically, provided is a novel process for the preparation of2-(2-nitrophenylazo) substituted phenols of the formula (VI)

[0184] which process comprises combining an ortho-nitroaniline offormula (VII)

[0185] a phenol of formula (VIII)

[0186] a nitrosating agent

[0187] together in a multiphase reaction medium and reacting the mixturefor a sufficient time without isolation of intermediate products,

[0188] wherein the multiphase medium comprises an organic and an aqueousphase and optionally a surface active agent;

[0189] wherein

[0190] G₁ is hydrogen or chloro, p1 G₂ is perfluoroalkyl (C_(n)F_(2n+1))where n is equal to 1-12, hydrogen, halogen, NO₂, cyano, R₃S—, R₃SO—,R₃SO₂—, phenyl, naphthyl, biphenylyl, 9-phenanthryl or said phenyl,naphthyl, biphenylyl or 9-phenanthryl substituted by one to three alkylof 1 to 18 carbon atoms, phenylalkyl of 7 to 15 carbon atoms, R₃S—,R₃SO—, R₃SO₂, aryl of 6 to 10 carbon atoms, perfluoroalkyl of 1 to 12carbon atoms, halogen, nitro, cyano, carboxyl, alkoxycarbonyl of 2 to 19carbon atoms, hydroxyl, alkoxy of 1 to 18 carbon atoms, aryloxy of 6 to10 carbon atoms, aralkoxy of 7 to 15 carbon atoms, vinyl, acetyl,acetamido, amino, dialkylamino of 2 to 12 carbon atoms, formyl,thioalkoxy of 1 to 18 carbon atoms, hydroxymethyl, aminomethyl,halomethyl, sulfato, phosphato or where any two substituents form abenzo ring with the aryl moiety to which they are attached,

[0191] R₁ is hydrogen, straight or branched chain alkyl of 1 to 24carbon atoms, straight or branched chain alkenyl of 2 to 24 carbonatoms, cycloalkyl of 5 to 12 carbon atoms, phenylalkyl of 7 to 15 carbonatoms, phenyl, or said phenyl or said phenylalkyl substituted on thephenyl ring by one to three alkyl of 1 to 4 carbon atoms; or R₁ is alkylof 1 to 24 carbon atoms substituted by one or two hydroxy groups,

[0192] R₂ is straight or branched alkyl chain of 1 to 24 carbon atoms,straight or branched chain alkenyl of 2 to 18 carbon atoms, cycloalkylof 5 to 12 carbon atoms, phenylalkyl of 7 to 15 carbon atoms, phenyl, orsaid phenyl or said phenylalkyl substituted on the phenyl ring by one tothree alkyl of 1 to 4 carbon atoms; or R₂ is said alkyl of 1 to 24carbon atoms or said alkenyl of 2 to 18 carbon atoms substituted by oneor more —OH, —OCOE₁₁, —OE₄, —NCO, —NHCOE₁₁ or —NE₇E₈, or mixturesthereof, where E₄ is straight or branched chain alkyl of 1 to 24 carbonatoms; alkenyl of 2 to 18 carbon atoms; or said alkyl or said alkenylinterrupted by one or more O, NH or NE₄-groups or mixtures thereof andwhich can be unsubstituted or substituted by one or more —OH, —OE₄ or—NH₂ groups or mixtures thereof; or R₂ is —(CH₂)_(m)—CO—E₅;

[0193] R₃ is alkyl of 1 to 20 carbon atoms, hydroxyalkyl of 2 to 20carbon atoms, alkenyl of 3 to 18 carbon atoms, cycloalkyl of 5 to 12carbon atoms, phenylalkyl of 7 to 15 carbon atoms, aryl of 6 to 10carbon atoms or said aryl substituted by one or two alkyl of 1 to 4carbon atoms;

[0194] E₅ is OE₆ or NE₇E₈, or E₅ is —PO(OE₁₂)₂, —OSi(E₁₁)₃ or —OCO—E₁₁,or straight or branched chain C₁-C₂₄alkyl which can be interrupted by—O—, —S— or —NE₁₁ and which can be unsubstituted or substituted by —OHor —OCO—E₁₁, C₅-C₁₂ cycloalkyl which is unsubstituted or substituted by—OH, straight chain or branched C₂-C₁₈alkenyl which is unsubstituted orsubstituted by —OH, C₇-C₁₅aralkyl, —CH₂—CHOH—E₁₃ or glycidyl,

[0195] E₆ is hydrogen, straight or branched chain C₁-C₂₄alkyl which isunsubstituted or substituted by one or more OH, OE₄ or NH₂ groups, or—OE₆ is —(OCH₂CH₂)_(w)OH or —(OCH₂CH₂)_(w)OE₂₁ where w is 1 to 12 andE₂₁ is alkyl of 1 to 12 carbon atoms,

[0196] E₇ and E₈ are independently hydrogen, alkyl of 1 to 18 carbonatoms, straight or branched chain alkenyl of 2 to 18 carbon atoms,straight or branched chain C₃-C₁₈alkyl which is interrupted by —O—, —S—or —NE₁₁, C₅-C₁₂cycloalkyl, C₆-C₁₄aryl or C₁-C₃hydroxylalkyl, or E₇ andE₈ together with the N atom are a pyrrolidine, piperidine, piperazine ormorpholine ring, or

[0197] E₅ is —X—(Z)_(p)—Y—E₁₅ wherein

[0198] X is —O— or —N(E₁₆)—,

[0199] Y is —O— or —N(E₁₇)—,

[0200] Z is C₂-C₁₂-alkylene, C₄-C₁₂-alkylene interrupted by one to threenitrogen atoms, oxygen atoms or a mixture thereof, or isC₃-C₁₂-alkylene, butenylene, butynylene, cyclohexylene or phenylene,each substituted by a hydroxyl group,

[0201] m is zero, 1 or 2,

[0202] p is 1, or p is also zero when X and Y are —N(E₁₆)— and —N(E₁₇)—,respectively,

[0203] E₁₅ is a group —CO—C(E₁₈)═C(H)E₁₉ or, when Y is —N(E₁₇)—, formstogether with E₁₇ a group —CO—CH═CH—CO—, wherein E₁₈ is hydrogen ormethyl, and E₁₉ is hydrogen, methyl or —CO—X—E₂₀, wherein E₂₀ ishydrogen, C₁-C₁₂-alkyl, and E₁₆ and E₁₇ independently of one another arehydrogen, C₁-C₁₂-alkyl, C₃-C₁₂-alkyl interrupted by 1 to 3 oxygen atoms,or is cyclohexyl or C₇-C₁₅aralkyl, and E₁₆ together with E₁₇ in the casewhere Z is ethylene, also forms ethylene,

[0204] E₁₁ is hydrogen, straight or branched chain C₁-C₁₈alkyl,C₅-C₁₂cycloalkyl, straight or branched chain C₂-C₁₈alkenyl, C₆-C₁₄arylor C₇-C₁₅aralkyl,

[0205] E₁₂ is straight or branched chain C₁-C₁₈alkyl, straight orbranched chain C₃-C₁₈alkenyl, C₅-C₁₀cycloalkyl, C₆-C₁₆aryl orC₇-C₁₅aralkyl, and

[0206] E₁₃ is H, straight chain or branched C₁-C₁₈alkyl which issubstituted by —PO(OE₁₂)₂, phenyl which is unsubstituted or substitutedby OH, C₇-C₁₅aralkyl or —CH₂OE₁₂.

[0207] Halogen is for example chloro, fluoro or bromo.

[0208] For instance, provided is a process for the preparation of acompound of formula (VIa)

[0209] which process comprises combining an ortho-nitroaniline compoundof formula (VIIa)

[0210] a phenol of formula (VIIIa)

[0211] a nitrosating agent selected from concentrated sulfuric acidsolution and sodium nitrite or nitrosylsulfuric acid,

[0212] together in a two phase reaction medium comprising an organic andan aqueous phase and a surface active agent and reacting the mixture fora sufficient time without isolation of intermediate products.

[0213] A particular embodiment of the invention produces a compound offormula (VI) or (VIa) wherein

[0214] G₁ is hydrogen,

[0215] G₂ is —CF₃, halogen or hydrogen,

[0216] R₁ is phenylalkyl of 7 to 15 carbon atoms, phenyl, or said phenylor said phenylalkyl substituted on the phenyl ring by one to three alkylof 1 to 4 carbon atoms,

[0217] R₂ is straight or branched alkyl chain of 1 to 24 carbon atoms,straight or branched chain alkenyl of 2 to 18 carbon atoms, cycloalkylof 5 to 12 carbon atoms, phenylalkyl of 7 to 15 carbon atoms, phenyl, orsaid phenyl or said phenylalkyl substituted on the phenyl ring by one tothree alkyl of 1 to 4 carbon atoms; or E₂ is said alkyl of 1 to 24carbon atoms or said alkenyl of 2 to 18 carbon atoms substituted by oneor more —OH, —OCOE₁₁, —OE₄, —NCO, —NH₂, —NHCOE₁₁, —NHE₄ or —N(E₄)₂, ormixtures thereof, where E₄ is straight or branched chain alkyl of 1 to24 carbon atoms; or said alkyl or said alkenyl interrupted by one ormore —O—, —NH— or —NE₄— groups or mixtures thereof and which can beunsubstituted or substituted by one or more —OH, —OE₄ or —NH₂ groups ormixtures thereof; and

[0218] R₃ is hydrogen; or a compound of formula (VI) or (VIa) wherein,

[0219] G₁ is hydrogen,

[0220] G₂ is —CF₃, halogen or hydrogen,

[0221] R₁ is hydrogen or straight or branched alkyl of 4 to 24 carbonatoms, and

[0222] R₂ and R₃ are as defined above.

[0223] In an alternative embodiment, the compound of formula (VI) or(VIa) is produced such that

[0224] G₁ is hydrogen,

[0225] G₂ is —CF₃ or halogen,

[0226] R₁ is hydrogen, straight or branched alkyl of 4 to 24 carbonatoms or phenylalkyl of 7 to 15 carbon atoms,

[0227] R₂ is —(CH₂)_(m)—CO—E₅,

[0228] R₃ is hydrogen,

[0229] E₅ is —OE₆ or —NE₇E₈, or

[0230] E₅ is —X—(Z)_(p)—Y—E₁₅

[0231] wherein

[0232] X is —O— or —N(E₁₆)—,

[0233] Y is —O— or —N(E₁₇)—,

[0234] Z is C₂-C₁₂-alkylene, C₄-C₁₂-alkylene interrupted by one to threenitrogen atoms, oxygen atoms or a mixture thereof, or isC₃-C₁₂-alkylene, butenylene, butynylene, cyclohexylene or phenylene,each substituted by a hydroxyl group,

[0235] m is 0, 1, 2 or 3,

[0236] p is 1, or p is also zero when X and Y are —N(E₁₆)— and —N(E₁₇)—,respectively,

[0237] E₁₅ is a group —CO—C(E₁₈)═C(H)E₁₉ or, when Y is —N(E₁₇)—, formstogether with E₁₇ a group —CO—CH═CH—CO—, wherein E₁₈ is hydrogen ormethyl, and E₁₉ is hydrogen, methyl or —CO—X—E₂₀, wherein E₂₀ ishydrogen, C₁-C₁₂-alkyl.

[0238] In a still further embodiment, the compound of formula (VI) or(VIa) is where

[0239] G₁ is hydrogen,

[0240] G₂ is —CF₃,

[0241] R₁ is phenylalkyl of 7 to 15 carbon atoms, phenyl, or said phenylor said phenylalkyl substituted on the phenyl ring by one to three alkylof 1 to 4 carbon atoms,

[0242] R₂ is straight or branched alkyl chain of 1 to 24 carbon atoms,straight or branched chain alkenyl of 2 to 18 carbon atoms, cycloalkylof 5 to 12 carbon atoms, phenylalkyl of 7 to 15 carbon atoms, phenyl, orsaid phenyl or said phenylalkyl substituted on the phenyl ring by one tothree alkyl of 1 to 4 carbon atoms; or E₂ is said alkyl of 1 to 24carbon atoms or said alkenyl of 2 to 18 carbon atoms substituted by oneor more —OH, —OCOE₁₁, —NH₂ or —NHCOE₁₁, or mixtures thereof, or saidalkyl or said alkenyl interrupted by one or more —O— and which can beunsubstituted or substituted by one or more —OH; R₃ is hydrogen; or is acompound of formula (VI) or (VIa) wherein,

[0243] G₁ is hydrogen,

[0244] G₂ is —CF₃,

[0245] R₁ is hydrogen, straight or branched alkyl of 4 to 24 carbonatoms or phenylalkyl of 7 to 15 carbon atoms, and

[0246] R₂ and R₃ are as defined above.

[0247] A further embodiment is the compound of formula (VI) or (VIa)where

[0248] G₁ is hydrogen,

[0249] G₂ is —CF₃,

[0250] R₁ is hydrogen, straight or branched alkyl of 4 to 24 carbonatoms or phenylalkyl of 7 to 15 carbon atoms,

[0251] R₂ is —(CH₂)_(m)—CO—E₅,

[0252] R₃ is hydrogen,

[0253] E₅ is —OE₆ or —NE₇E₈ where

[0254] E₆ is hydrogen, straight or branched chain C₁-C₂₄alkyl which isunsubstituted or substituted by one or more OH groups, or —OE₆ is—(OCH₂CH₂)_(w)OH or —(OCH₂CH₂)_(w)OE₂₁ where w is 1 to 12 and E₂₁ isalkyl of 1 to 12 carbon atoms, and

[0255] E₇ and E₈ are independently hydrogen, alkyl of 1 to 18 carbonatoms, straight or branched chain C₃-C₁₈alkyl which is interrupted by—O—, —S— or —NE₁₁—, C₅-C₁₂cycloalkyl, C₆-C₁₄aryl or C₁-C₃hydroxylalkyl,or E₇ and E₈ together with the N atom are a pyrrolidine, piperidine,piperazine or morpholine ring.

[0256] Provided is a process for the preparation of a compound offormula (VIb)

[0257] which process comprises combining an ortho-nitroaniline compoundof formula (VIIb)

[0258] a phenol of formula (VIIIb)

[0259] nitrosylsulfuric acid in sulfuric acid

[0260] together in a two phase reaction medium comprising an organic andan aqueous phase and a surface active agent and reacting the mixture fora sufficient time without isolation of intermediate products;

[0261] wherein G₂ is CF₃, hydrogen, fluorine, chlorine or bromine.

[0262] In this case the nitrosating agent, nitrosylsulfuric acid insulfuric acid, may be added as an aqueous or an acid solution.

[0263] Provided is a process for the preparation of a compound offormula (VIc)

[0264] which process comprises combining an ortho-nitroaniline compoundof formula (VIIc)

[0265] a phenol of formula (VIIIc)

[0266] nitrosylsulfuric acid in the form of an acid solution,

[0267] together in a two phase reaction medium comprising an organic andan aqueous phase and a surface active agent and reacting the mixture fora sufficient time without isolation of intermediate products.

[0268] As discussed supra, intermediate products in the present processfor the preparation of compounds of formula (VI) are not isolated.Specifically, diazonium salt products of the ortho-nitroaniline are notisolated.

[0269] In the present process where the nitrosating agent is sulfuricacid and alkali metal nitrite (i.e. sodium nitrite), the followingprocess parameters pertain:

[0270] a. The molar ratio of nitroaniline:sulfuric acid is 1:10 to 1:1;for example 1:5 to 1:1; and for instance 1:3.5.

[0271] b. The molar ratio of nitroaniline:sodium nitrite is 1:1 to 1:4;for example 1:1 to 1:2; for instance 1:1.

[0272] c. The temperature used for this reaction is from −30° C. to 50°C.; for example from −20° C. to 20° C.; for instance from −10° C. to 5°C.

[0273] Ib. In the process for the in situ generation of diazonium saltsusing a substituted ortho-nitroaniline and nitrosylsulfuric acid insulfuric acid, the following process parameters pertain:

[0274] a. The molar ratio of nitroaniline:nitrosylsulfuric acid is 1:1to 1:2; for example 1:1 to 1:1.2; for instance 1:1.

[0275] b. The molar ratio of nitroaniline:sulfuric acid is 1:1 to 1:10;for example 1:2 to 1:7; for instance 1:2 to 1:5.

[0276] c. The temperature used for this reaction is from −30° C. to 50°C.; for example from −20° C. to 40° C.; for instance from 0° C. to 25°C.

[0277] When the nitrosating agent is nitrosylsulfuric acid and sulfuricacid, the concentration of the solution is under 90% sincenitrosylsulfuric acid can decompose to form nitric oxide (NO_(x)) gasesbefore it has time to react with the nitroaniline. A precharge ofsulfuric acid may be used to limit the decomposition of nitrosulfuricacid and hence facilitate the diazotization reaction.

[0278] The present mixture is conveniently reacted at a temperature of−30° C. to 75° C.; for example at −20° C. to 50° C.; for instance at−10° C. to 35° C.

[0279] The organic solvents for use in the present multiphase processare selected from aromatic hydrocarbons, aliphatic hydrocarbons ormixtures thereof. Different solvents may be used for the dispersion andaddition of phenolic compounds. For example, the organic solvent isligroine, toluene, o-xylene, m-xylene, p-xylene or a mixture of saidxylenes, mesitylene, pseudocumene, hexane, heptane, octane, nonane or amixture thereof. For instance, the solvent is ligroine, toluene,o-xylene, m-xylene, p-xylene, a mixture of said xylenes, heptane or amixture thereof. The amount of solvent is not critical, but making thesolution too dilute is to be avoided. The essential attribute of theorganic solvent is the ability to preferentially dissolve the phenoliccompounds. The solvent must also be water immiscible as shown by phaseseparation when stirring is stopped.

[0280] The nitrosating agents are nitrosylsulfuric acid in an acidcarrier or an aqueous alkali metal nitrite, such as sodium nitrite in anacidic environment. The nitrosating agent is for example a mixture ofnitrosylsulfuric acid in sulfuric acid. Other appropriate acid carriersor acids include, without limitation, acetic acid, hydrochloric acid,fluoroboric acid. The ratio of organic solvent to water is for example2:1 to 1:2. The acid is present in the reaction system prior to theaddition of the nitrosating agent or added simultaneously therewith. Thesimultaneous addition can be done by separate addition or as a mixture(acid carrier). An acid carrier or acid environment is preferablypresent when preparing2-(2-nitrophenylazo) substituted phenols fromreagents characterized as electron deficient amines. Particular examplesof electron deficient amines are trifluoromethyl, halogen andnitro-substituted aromatic amines, most especially when substituted bysuch groups in the 4-position of the benzene ring. Organic solublebuffers or bases increase the reactivity of the phenol toward thecoupling reaction and limit the de-alkylation of the phenolic compound.

[0281] The surface active agent to be used is any one or a mixture ofmaterials selected from the group consisting of emulsifying agents,surfactants, phase transfer agents and dispersants. For instance, thesurface active modifier is at least one anionic surfactant. Suitableanionic surfactants include, for example, alcohol sulfates (e.g. alkalimetal or ammonium salts of alcohol sulfates) and sulfonates, alcoholphosphates and phosphonates, alkyl sulfonates, alkylaryl sulfonates,alkali metal or ammonium salts of fatty acids, sulfonated amines,sulfonated amides, fatty sarcosinates such as sodium lauroylsarcosinate, linear alkylated sulfonates such as alkylbenzene sulfonateswhere the R-group is attached between C₆-C₁₅, alcohol ether sulfatessuch as those with the structure R═C₈-C₁₅ and where ethoxylation isbetween 1-7, secondary alkane sulfonates such as the Hostapur® SASseries supplied by Clariant, and mixtures thereof. A more complete listof anionic surfactants is provided in McCutcheon's, Volume 1,Emulsifiers and Detergents, pp. 280-283 (1997), which is incorporatedherein by reference. HOSTAPUR® SAS93 (Hoechst), which is a secondaryalkane sulphonate sodium salt (paraffin sulphonate) or PETROSULS® M-60(Penreco), which are petroleum sulphonate salts, are specific examples.The amount used is that needed to ensure adequate dispersion of thenitroaniline within the organic phase of the reaction system.

[0282] The molar ratio of nitroaniline:phenol may be for example 2:1 to1:2; for example 1.5:1 to 1:1.5; for instance 1:1 to 1:0.85.

[0283] The 2-(2-nitrophenylazo) substituted phenol compounds of formula(VI) (monoazobenzene compounds) prepared by the instant process may beconveniently reduced to the corresponding benzotriazolyl-1-oxide andthen to the corresponding 2H-benzotriazole by any number of conventionalreduction methods. An illustrative list of such methods is given supra(references 1-17), and again should not be construed as being the onlymethods possible for carrying out said reduction.

[0284] Illustrative of the corresponding benzotriazole compounds thatcan be made from the 2-(2-nitrophenylazo) substituted phenols preparedby the present process are:

[0285] (1)5-trifluoromethyl-2-(2-hydroxy-3-α-cumyl-5-tert-octylphenyl)-2H-benzotriazole;

[0286] (2)5-trifluoromethyl-2-(2-hydroxy-5-tert-octylphenyl)-2H-benzotriazole;

[0287] (3)5-trifluoromethyl-2-(2-hydroxy-3,5-di-tert-octylphenyl)-2H-benzotriazole;

[0288] (4)5-trifluoromethyl-2-(2-hydroxy-5-(2-hydroxyethyl)phenyl)-2H-benzotriazole;

[0289] (5)5-trifluoromethyl-2-(2-hydroxy-3,5-di-α-cumylphenyl)-2H-benzotriazole;

[0290] (6)3-(5-trifluoromethyl-2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyhydrocinnamicacid;

[0291] (7) methyl3-(5-trifluoromethyl-2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyhydrocinnamate;

[0292] (8) isooctyl3-(5-trifluoromethyl-2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyhydrocinnamate;

[0293] (9)5-trifluoromethyl-2-[2-hydroxy-5-(3-hydroxypropyl)phenyl]-2H-benzotriazole;

[0294] (10)5-trifluoromethyl-2-[2-hydroxy-5-(3-acryloyloxypropyl)phenyl]-2H-benzotriazole;

[0295] (11)5-trifluoromethyl-2-[2-hydroxy-5-(3-methacryloyloxypropyl)phenyl]-2H-benzotriazole;

[0296] (12)5-trifluoromethyl-2-[2-hydroxy-5-(3-acrylylaminopropyl)phenyl]-2H-benzotriazole;

[0297] (13)5-trifluoromethyl-2-[2-hydroxy-5-(3-methacrylylaminopropyl)phenyl]-2H-benzotriazole;

[0298] (14)5-trifluoromethyl-2-(2-hydroxy-3-α-cumyl-5-tert-butylphenyl)-2H-benzotriazole;

[0299] (15)5-trifluoromethyl-2-(2-hydroxy-3-α-cumyl-5-nonylphenyl)-2H-benzotriazole;

[0300] (16)5-trifluoromethyl-2-[2-hydroxy-3-α-cumyl-5-(2-hydroxyethyl)phenyl]-2H-benzotriazole;

[0301] (17)5-trifluoromethyl-2-[2-hydroxy-3-α-cumyl-5-(3-hydroxypropyl)phenyl]2H-benzotriazole;

[0302] (18)5-trifluoromethyl-2-(2-hydroxy-3,5-di-tert-amylphenyl)-2H-benzotriazole;

[0303] (19)5-trifluoromethyl-2-(2-hydroxy-3,5-di-tert-butylphenyl)-2H-benzotriazole;

[0304] (20)5-trifluoromethyl-2-(2-hydroxy-3-dodecyl-5-methylphenyl)-2H-benzotriazole;

[0305] (21)5-trifluoromethyl-2-[2-hydroxy-3-tert-butyl-5-(3-hydroxypropyl)phenyl)2H-benzotriazole;

[0306] (22)5-trifluoromethyl-2-[2-hydroxy-3-tert-butyl-5-(2-hydroxyethyl)phenyl]2H-benzotriazole;

[0307] (23) 5-fluoro-2-(2-hydroxy-5-methylphenyl)-2H-benzotriazole;

[0308] (24) 5-chloro-2-(2-hydroxy-5-methylphenyl)-2H-benzotriazole;

[0309] (25) 5-bromo-2-(2-hydroxy-5-methylphenyl)-2H-benzotriazole;

[0310] (26) 5-chloro-2-(2-hydroxy-5-tert-octylphenyl)-2H-benzotriazole;

[0311] (27) 5-bromo-2-(2-hydroxy-5-tert-octylphenyl)-2H-benzotriazole;

[0312] (28)5-chloro-2-(2-hydroxy-3,5-di-tert-butylphenyl)-2H-benzotriazole;

[0313] (29) 2-(2-hydroxy-5-methylphenyl)-2H-benzotriazole;

[0314] (30)5-fluoro-2-(2-hydroxy-3,5-di-tert-butylphenyl)-2H-benzotriazole;

[0315] (31)5-bromo-2-(2-hydroxy-3,5-di-tert-butylphenyl)-2H-benzotriazole;

[0316] (32) 2-(2-hydroxy-3,5-di-tert-butylphenyl)-2H-benzotriazole;

[0317] (33)5-chloro-2-(2-hydroxy-3,5-di-α-cumylphenyl)-2H-benzotriazole;

[0318] (34)5-fluoro-2-(2-hydroxy-3,5-di-α-cumylphenyl)-2H-benzotriazole;

[0319] (35)5-chloro-2-(2-hydroxy-3-α-cumyl-5-tert-octylphenyl)-2H-benzotriazole;

[0320] (36)5-bromo-2-(2-hydroxy-3-α-cumyl-5-tert-octylphenyl)-2H-benzotriazole;

[0321] (37)5-fluoro-2-(2-hydroxy-3-α-cumyl-5-tert-octylphenyl)-2H-benzotriazole;

[0322] (38) 2-(2-hydroxy-3-α-cumyl-5-tert-octylphenyl)-2H-benzotriazole;

[0323] (39) 5-chloro-2-(2-hydroxy-4-phenylphenyl)-2H-benzotriazole;

[0324] (40) 5-fluoro-2-(2-hydroxy-4-phenylphenyl)-2H-benzotriazole;

[0325] (41) 5-bromo-2-(2-hydroxy-4-phenylphenyl)-2H-benzotriazole;

[0326] (42) 2-(2-hydroxy-3,5-di-α-cumylphenyl)-2H-benzotriazole;

[0327] (43)5-chloro-2-[2-hydroxy-3-tert-butyl-5-(3-hydroxypropyl)phenyl]-2H-benzotriazole;

[0328] (44)5-fluoro-2-[2-hydroxy-3-tert-butyl-5-(3-hydroxypropyl)phenyl]-2H-benzotriazole;

[0329] (45)5-bromo-2-[2-hydroxy-3-tert-butyl-5-(3-hydroxypropyl)phenyl]-2H-benzotriazole;

[0330] (46)2-[2-hydroxy-3-tert-butyl-5-(3-hydroxypropyl)phenyl]-2H-benzotriazole;

[0331] (47)3-(5-chloro-2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyhydrocinnamicacid;

[0332] (48)3-(5-bromo-2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyhydrocinnamicacid;

[0333] (49)3-(5-fluoro-2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyhydrocinnamicacid;

[0334] (50) 3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyhydrocinnamicacid;

[0335] (51)3-(5-chloro-2H-benzotriazol-2-yl)-5-α-cumyl-4-hydroxyhydrocinnamic acid;

[0336] (52)3-(5-bromo-2H-benzotriazol-2-yl)-5-α-cumyl-4-hydroxyhydrocinnamic acid;

[0337] (53)3-(5-fluoro-2H-benzotriazol-2-yl)-5-α-cumyl-4-hydroxyhydrocinnamic acid;

[0338] (54) methyl3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyhydrocinnamate;

[0339] (55) methyl3-(5-chloro-2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyhydrocinnamate;

[0340] (56) methyl3-(5-chloro-2H-benzotriazol-2-yl)-5-α-cumyl-4-hydroxyhydrocinnamate;

[0341] (57)5-chloro-2-(2-hydroxy-3,5-di-tert-amylphenyl)-2H-benzotriazole;

[0342] (58)5-fluoro-2-(2-hydroxy-3,5-di-tert-amylphenyl)-2H-benzotriazole;

[0343] (59)5-bromo-2-(2-hydroxy-3,5-di-tert-amylphenyl)-2H-benzotriazole;

[0344] (60) 2-(2-hydroxy-3,5-di-tert-amylphenyl)-2H-benzotriazole;

[0345] (61)5-phenylsulfonyl-2-(2-hydroxy-3,5-di-tert-butylphenyl)-2H-benzotriazole;

[0346] (62)5-octylsulfonyl-2-(2-hydroxy-3,5-di-tert-butylphenyl)-2H-benzotriazole;

[0347] (63)5-phenylsulfonyl-2-(2-hydroxy-3,5-di-α-cumylphenyl)-2H-benzotriazole;

[0348] (64)5-phenylsulfonyl-2-(2-hydroxy-3,5-di-α-cumylphenyl)-2H-benzotriazole;

[0349] (66)5-octylsulfonyl-2-(2-hydroxy-3-α-cumyl-5-tert-octylphenyl)-2H-benzotriazole;

[0350] (67)5-butylsulfonyl-2-(2-hydroxy-3-α-cumyl-5-tert-octylphenyl)-2H-benzotriazole;

[0351] (68)5-ethylsulfonyl-2-(2-hydroxy-3-α-cumyl-5-tert-octylphenyl)-2H-benzotriazole;

[0352] (69)5-n-dodecylsulfonyl-2-(2-hydroxy-3,5-di-tert-butylphenyl)-2H-benzotriazole;

[0353] (70) 5,5′-sulfonyl-bis[2-(2-hydroxy-3-α-cumyl-5-tert-octylphenyl)-2H-benzotriazole];

[0354] (71) octyl3-(5-phenylsulfonyl-2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyhydrocinnamate;

[0355] (72)3-(5-phenylsulfonyl-2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyhydrocinnamamide; or

[0356] (73)5-phenylsulfonyl-2-[2-hydroxy-3-tert-butyl-5-(3-hydroxypropyl)phenyl]-2H-benzotriazole;

[0357] (74) 2-(2-hydroxy-3,5-di-tert-octylphenyl)-2H-benzotriazole;

[0358] (75) 2-(2-hydroxy-5-tert-octylphenyl)-2H-benzotriazole;

[0359] (76) isooctyl3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyhydrocinnamate; and

[0360] (77)2-(3-t-butyl-2-hydroxy-5-(2-(ω-hydroxy-octa-(ethyleneoxy)carbonyl-ethyl)-,phenyl)-2H-benzotriazole, Tinuvin® 1130.

[0361] The following examples are for illustrative purposes only and arenot to be construed to limit the scope of the instant invention in anymanner whatsoever.

[0362] Examples 1-14 pertain to the improved process for the preparationof 5-perfluoroalkyl (for example trifluoromethyl) substituted2H-benzotriazoles.

[0363] There are four generic procedures outlined in the Examplesillustrating various methods of making the diazonium salts which areused to produce the desired monoazobenzene compounds by coupling withthe appropriate phenol.

EXAMPLE 1 2-Nitrobenzenediazonium Chloride

[0364] To a laboratory reactor equipped with the necessary auxiliaryattachments is added 206.4 g (32% by weight, 1.81 mol) of hydrochloricacid. o-Nitroaniline (82.6 g, 0.60 mol, ONA, Aldrich Chemical Co.) isadded slowly to the well-stirred solution. An exotherm temperature of40-50° C. occurs. After dissolution of the ONA is complete, ice (104 g,5.78 mol) is charged and cooling is applied. At a temperature of −15° C.to −10° C., sodium nitrite (37.5 g, 0.60 mol) is charged slowly over aone-hour period while maintaining the temperature at −15° C. to −10° C.The resulting solution is clarified through a bed of Solka Floc (groundcellulose). A light yellow aqueous diazonium chloride salt solution isobtained in a yield of 410 g and is stored at about −15° C. to −10° C.till later use.

EXAMPLE 2 5-Trifluoromethyl-2-nitrobenzenediazonium Chloride

[0365] Following a procedure similar to that of Example 1,o-nitroaniline (ONA) is replaced with 4-trifluoromethyl-2-nitroaniline(CF₃—ONA). When 41.2 g of CF₃—ONA (Aldrich Chemical Co.) is used, thetitle compound is obtained in a yield of 205 g as an aqueous solutionand is stored at −15° C. to −10° C. till later use.

EXAMPLE 3 5-Trifluoromethyl-2-nitrobenzenediazonium Bisulfate

[0366] To a laboratory reactor equipped with necessary ancillaryequipment, 93% sulfuric acid (99.5 g, 0.94 mol) is charged.4-Trifluoromethyl-2-nitroaniline (63.9 g, 0.30 mol, obtained fromAldrich Chemical Co.) is added slowly to the well-stirred reaction mass.The reaction mass is heated to 70-75° C. to ensure complete dissolution.At this temperature, water (200 g, 11.1 mol) is added slowly whilemaintaining the temperature at 70-75° C. The reaction mixture is cooledto 0-5° C. at which time sodium nitrite (54.3 g, 0.32 mol, as a 40%aqueous solution) is charged over a two-hour period. The temperatureshould be kept in this temperature range since an exotherm can occur ifthe temperature is not monitored carefully. The resulting yellowsolution is clarified through a bed of Solka Floc (ground cellulose).The yellow aqueous diazonium salt solution (400 g) is obtained andstored at −15° C. to -10° C. till later use.

EXAMPLE 4 5-Trifluoromethyl-2-nitrobenzenediazonium Bisulfate

[0367] To a laboratory reactor equipped with the necessary ancillaryequipment, nitrosylsulfuric acid (384.7 g, 1.20 mol, 40% solution insulfuric acid, obtained from Aldrich Chemical Co. or synthesized beforeuse) and concentrated 98% sulfuric acid (287.3 g, 2.73 mol) are charged.To the above solution well-stirred and cooled to 10-15° C.,4-trifluoromethyl-2-nitroaniline (250.7 g, 1.20 mol, obtained fromAldrich Chemical Co.) is charged portion-wise over one to two hourswhile maintaining the temperature at 0° C. Ice (700 g, 38.9 mol) ischarged slowly and the excess nitrosylsulfuric acid is destroyed withsulfamic acid. The yellow solution formed is clarified through asintered glass funnel. The reactor and funnel are rinsed with cold water(100 g, 5.6 mol) and combined with the diazonium salt solution. Thetitle compound is prepared in a yield of 1777.9 g as a yellow, aqueoussolution which is stored at −15° C. to −10° C. until later use.

[0368] Examples 5-12 show the preparation of selected monoazobenzenecompounds which are intermediates for preparing the corresponding2H-benzotriazole UV abosrbers.

EXAMPLE 5 2-Hydroxy-2′-nitro-4′-trifluoromethyl-5-tert-octylazobenzene

[0369] To a laboratory reactor equipped with the necessary auxiliaryequipment, 4-tert-octyl-phenol (36.0 g, 0.17 mol, obtained from AldrichChemical Co.), xylenes (90 g, 0.84 mol) and HOSTAPUR® SAS93 (1.5 g,surfactant, Hoechst Corp.) are charged. The reaction mixture is cooledto 10° C. at which time the diazonium salt solution, prepared in Example2, (303 g, 0.17 mol, as a 14.3% solution) is charged over a three-hourperiod. The aqueous layer is separated after heating the reaction massto 45° C. The xylene phase is analyzed for the title compound;standardized HPLC analysis reveals a 23.7% yield of the title compound.

EXAMPLE 62-Hydroxy-2′-nitro-4′-trifluoromethyl-3,5-di-tert-butylazobenzene

[0370] To a laboratory reactor equipped with the necessary auxiliaryequipment, 2,4-di-tert-butylphenol (47.1 g, 0.22 mol, obtained fromSchenectady Chemical Co.), xylenes (80 g, 0.75 mol) and PETROSUL® M-60(1.8 g, surfactant, Penreco) are charged. At ambient temperature (20-25°C.), the diazonium salt solution prepared in Example 3 (344 g, 0.24 mol)is charged over a 4.25 hour period while continuing agitation foranother six hours. Xylenes (300 g, 2.83 mol) and sodium hydroxide (183g, 1.14 mol as a 25% aqueous solution) are charged while heating to 75°C. The aqueous layer is removed and the organic layer is subjected tovacuum distillation to remove xylenes. The crimson red oil obtained iscrystallized from 120 g of methanol at 0° C. The solids are filtered andwashed with 300 g of cold methanol. After vacuum drying, the titlecompound is prepared in 86.8% yield (82.3 g) as a solid melting at 105°C. The structure is verified by ¹Hnmr and mass spectrometry analyses.

EXAMPLE 7 2-Hydroxy-2′-nitro-4′-trifluoromethyl-4,5-dimethylazobenzene(major) 2-Hydroxy-2′-nitro-4′-trifluoromethyl-5,6-dimethylazobenzene(minor)

[0371] Following the procedure of Example 6, 3,4-dimethylphenol (27.8 g,0.23 mol) is substituted for 2,4-di-tert-butylphenol. The titlecompounds are obtained as 67.4 g, 86.4% yield as a crimson solid and isa 83:17 mixture of the two indicated regioisomers as judged by ¹Hnmranalysis.

EXAMPLE 8 2-Hydroxy-2′-nitro-5-methylazobenzene

[0372] To a laboratory reactor equipped with the necessary auxiliaryequipment, water (698 g, 38.8 mol), sodium hydroxide (49.2 g, 0.61 molas a 50% aqueous solution) and p-cresol (66.9 g, 0.62 mol) are charged.After cooling to 0° C., the diazonium salt solution prepared in Example1 (444 g, 0.60 mol as a 25% aqueous solution) is added over 3.5 hours.During the latter two hours of addition a pH of 8.0-9.0 is maintained(47.6 g of 50% aqueous sodium hydroxide is required.). Xylenes (310 g,2.92 mol) and water (150 g, 8.33 mol) are charged while heating thesolution to 84-86° C. The aqueous layer is removed and the organic layeris washed once with 300 g of water. The xylene phase is dried byazeotropic distillation. The title compound is obtained as a crimson redxylene solution (370 g, 96.1% yield as a 40% by weight solution).

EXAMPLE 9 2-Hydroxy-2′-nitro-4′-trifluoromethyl-5-tert-octylazobenzene

[0373] To a laboratory reactor equipped with the necessary ancillaryequipment, xylenes (188.4 g, 1.78 mol), methanol (5.4 g, 0.17 mol),water (120 g, 6.67 mol), acetic acid (60 g, 1.0 mol) andp-tert-octylphenol (56.9 g, 0.28 mol) are charged. After cooling to −5°C., the diazonium salt solution prepared in Example 4 (424.2 g, 0.27 molas a 19.7% aqueous solution) and sodium hydroxide (473 g, 2.37 mol as a20% aqueous solution) are charged simultaneously over three hours. Athirty gram water rinse is charged after completion of the diazoniumsalt solution addition. The reaction mass is allowed to warm to 5° C.over two hours with continued stirring. Xylenes (50 g, 0.47 mol) isadded following by heating to 40° C. The water phase is split off andthe desired product is isolated from the xylene phase. The titlecompound is prepared as a crimson solid (82.7 g, 73.8% yield) whosestructure is consistent with ¹Hnmr analysis.

EXAMPLE 102-Hydroxy-2′-nitro-4′-trifluoromethyl-3-α-cumyl-5-tert-octylazobenzene

[0374] To a laboratory reactor equipped with the necessary ancillaryequipment, xylenes (411.7 g, 3.88 mol), 2-α-cumyl-4-tert-octylphenol(232.8 g, 0.69 mol) and HOSTAPUR® SAS 93 (9.7 g, surfactant, HoechstCorp.) are charged. After cooling to 0-5° C., the diazonium saltsolution prepared in Example 4 (1115.4 g, 0.68 mol)is added over a 3.75hour period. While the diazonium salt solution is added, the reactionmass is homogenized with an Ultra-turax homogenizer. After the diazoniumsalt solution addition is complete, agitation is continued for anothertwo hours. The reaction mass is heated to 55° C. and the aqueous layeris split off. From the organic phase, the title compound is obtained asa crimson red solid (282.9 g, 76.4% yield) melting at 101-105° C.

[0375] Examples 6 and 7 show that the diazonium salts produced usingsulfuric acid and sodium nitrite as seen in Example 3 are useful forcoupling with phenols having lower alkyl substitution (such as3,4-dimethylphenol in Example 7 or 2,4-di-tert-butylphenol in Example6). Examples 11 and 12 show that diazonium salts as prepared in Example3 are not useful for coupling with phenols having longer alkyl chains(such as 4-tert-octylphenol) even though 2,4-di-tert-butylphenol and4-tert-octylphenol have the same total number of alkyl carbon atoms assubstituents.

EXAMPLE 11 2-Hydroxy-2′-nitro-4′-trifluoromethyl-5-tert-octylazobenzene

[0376] To a laboratory reactor equipped with the necessary auxiliaryequipment, xylenes (201.4 g, 1.90 mol), p-tert-octylphenol (82.6 g, 0.39mol) and HOSTAPUR® SAS 93 (3.4 g, surfactant, Hoechst Corp.) arecharged. After cooling to 10-12° C., the diazonium salt solutionprepared in Example 3 (874.9 g, 0.39 mol as a 14.05% aqueous solution)is added over a three-hour period. The reaction mass is heated to 25° C.and the aqueous layer is removed. The title compound is obtained fromthe xylene phase as a crimson solid in a yield of 61.47 g (37% yield).

EXAMPLE 12 2-Hydroxy-2′-nitro-4′-trifluoromethyl-5-tert-octylazobenzene

[0377] To a laboratory reactor equipped with the necessary auxiliaryequipment, xylenes (15.3 g, 0.14 mol), p-tert-octylphenol (32.5 g, 0.15mol), methanol (237.6 g, 7.42 mol), water (7.0 g, 0.39 mol) and sodiumhydroxide (63.6 g, 1.59 mol) are added. The temperature is reduced to−15° C. to −10° C. at which time the diazonium salt solution prepared inExample 3 (311.2 g, 0.195 mol as a 19.8% aqueous solution) is added overa four-hour period. Water (190 g, 10.6 mol) and xylenes (304.5 g, 2.87mol) are added while heating to 65° C. The aqueous layer is removed. Thetitle compound is isolated from the xylene phase as a crimson solid in ayield of 21.6 g (33.8% yield).

[0378] Examples 5, 9, 11 and 12 show the synthesis of the same monoazocompound, namely2-hydroxy-2′-nitro-4′-trifluoromethyl-5-tert-octylazobenzene, from thediazonium salt prepared from 4-trifluoro-2-nitroaniline (CF₃—ONA) andcoupled with 4-tert-octylphenol. The diazonium salt solutions areprepared by different preparative methods as shown in Examples 2, 3 and4. The yields for preparing the monoazo compounds are tabulated in theTable below showing that when a trifluoromethyl moiety is present thatmajor differences in yield occur depending on how the diazonium salt isprepared regardless of the coupling method. Diazonium Salt of Method ofMaking Example Diazonium Salt Monoazo Yield (%)  5 NaNO₂ + HCl 23.7 11NaNO₂ + H₂SO₄ 37*  12 NaNO₂ + H₂SO₄  33.8**  9 nitrosylsulfuric 73.8  10*** nitrosylsulfuric 76.4

[0379] It is clear that the use of nitrosylsulfuric acid in thepreparation of the diazonium salt where a trifluoromethyl moiety ispresent leads to far superior yields of the key monoazobenzeneintermediate needed to prepare the instant benzotriazole UV absorbers.

[0380] When the monoazo compound is2-hydroxy-2′-nitro-4′-trifluoromethyl-3,5-di-tert-butyl-azobenzene asseen in Example 6, the method of making the monoazo compound usingNaNO₂+H₂SO₄ leads to a yield of 86.8% in contrast to the yields of 37%and 33.8% when the monoazo compound is2-hydroxy-2′-nitro-4′-trifluoromethyl-5-tert-octylazobenzene made usingNaNO₂+H₂SO₄ as seen in Examples 11 and 12.

[0381] Examples 13 and 14 show that the monoazobenzene compounds of theinstant invention can be reduced to the desired 2H-benzotriazole UVabsorber in excellent yield using any of a number of conventionalmethods such as, for example, by catalytic hydrogenation using hydrogenin a basic medium or reduction using 2,3-dichloro-1,4-naphthoquinone.

EXAMPLE 135-Trifluoromethyl-2-(2-hydroxy-5-tert-octylphenyl)-2H-benzotriazole

[0382] To a laboratory autoclave equipped with the necessary auxiliaryequipment, the monoazo compound prepared in Example 9 (112.4 g, 0.25mol), xylenes (160 g, 1.51 mol), n-butylamine (110 g, 1.50 mol) andplatinum/palladium on carbon catalyst (1.5 g, Johnson Matthey Co.) areadded. At a temperature of 20-25° C., hydrogen is metered slowly intothe autoclave at a pressure of 30 psig. At the end of the reaction, thefinal reaction temperature is adjusted to 55° C. The hydrogen is ventedand the catalyst is removed by filtration. The n-butylamine is removedby distillation and the reaction mass is cooled to 60° C. at which timeit is washed with 134.5 g of 78% sulfuric acid. After splitting off theacid phase, the organic phase is washed twice with 200 g of water at65-75° C. The xylene phase is dried by azeotropic distillation and thentreated with 5 g of acidic alumina. After removal of the alumina, thexylene is distilled and replaced with 200 g of methanol and seeded. Theslurry is cooled to 0° C., filtered and washed with 200 g of methanoland dried overnight at 65° C. in a vacuum oven. The title compound isobtained as a white powder (71.8 g, 71.6% yield) with a melting point of80-81° C.

EXAMPLE 145-Trifluoromethyl-2-(2-hydroxy-3-α-cumyl-5-tert-octylphenyl)-2H-benzotriazole

[0383] To a laboratory reactor equipped with the necessary auxiliaryequipment, 2-butanol (700 g, 9.46 mol) and sodium hydroxide pellets(23.7 g, 0.59 mol) are charged and heated to reflux. A solution of themonoazo compound prepared in Example 10 (122.4 g, 0.22 mol),2,3-dichloro-1,4-naphthoquinone (5.6 g, 0.025 mol from the AldrichChemical Co.), heptane (342 g, 3.41 mol) and methyl ethyl ketone (402.5g, 5.6 mol) is added to the refluxing solution over a two-hour periodwhile distilling off methyl ethyl ketone and heptane. After the reactionis complete, the temperature is reduced to 45-50° C. at which time thereaction mass is neutralized with 30% aqueous sulfuric acid. Thetemperature is reduced to 25° C. and the reaction mass is seeded. Aftercooling to 5° C., the slurry is filtered and washed with 232 g of hotwater. The filter cake is allowed to cool to ambient temperature and isthen washed with 200 g of cold methanol and dried in a vacuum oven. Thetitle compound is prepared in a yield of 92.8 g, 79.1% yield and has amelting point of 119-121° C.

[0384] Examples 15-30 pertain to the present one-pot process for thepreparation of 2-(2-nitrophenylazo) phenols.

EXAMPLE 152-(2-nitro-4-trifluoromethyl-phenylazo)-6-(1-methyl-1-phenyl-ethyl)-4-(1,1,3,3-tetramethyl-butyl)-phenol

[0385] To a 1 L lab flask are added 54.6 g (0.26 mol, 99.9%) of4-trifluoromethyl-2-nitroaniline, PETROSUL H-60 (5.3 g dissolved in121.4 g water), 2-cumyl-4-tert-octylphenol (80.9 g, 0.25 mol, 92.5%) andligroine (241.7 g, bp 90-110 ° C.). Sulfuric acid (32.7 g, 93%) ischarged to the reactor with stirring. The reaction mass is cooled to 5 °C. Nitrosylsulfuric acid (94.4 g, 0.30 mol, 40% in sulfuric acid) andwater (84.5 g) are added via a peristaltic pump over 8 hours. Thecooling bath is removed and the reaction mass is allowed to warm to roomtemperature overnight. The reaction mass is heated to 40° C. Stirring isstopped and the two phases separate. Removed the aqueous layer. Theligroine layer weighed 373.8 g and contained 25.73 weight % of desiredproduct (96.2 g of monoazo corresponding to a yield of 77% based onphenol as determined by calibrated HPLC analysis). The product may becrystallized from hot methanol, resulting in a burgundy solid with amelting point of 101-105° C. as per co-pending application 09/632,217example 10. ¹H-NMR (CDCl₃; 499.8494 MHz): δ0.85 (s, 9H); δ1.42 (s, 6H);δ1.77 (s, 2H); δ1.78 (s, 6H); δ7.14-7.30 (multiplet, 5H); δ7.50 (d, 1H);δ7.58 (d, 1H); δ7.90 (d, 1H); δ8.15 (d, 1H); δ8.37 (s, 1H).

Comparative Example 15c2-(2-nitro-4-trifluoromethyl-phenylazo)-6-(1-methyl-1-phenyl-ethyl)-4-(1,1,3,3-tetramethyl-butyl)-phenol

[0386] Published British patent 2,319,035 (example) 1 reports a yield of42.1 g of a paste. As demonstrated above the desired product is a solidwith a well defined melting point. The fact that the product is a pasteindicates that the monoazo obtained in GB 2,319,035 is impure. Thepurity is not specified. The yield of the paste of unknown purity is38.5% based on 4-trifluoromethyl-2-nitroaniline using the traditionalbase coupling route.

EXAMPLE 162-(2-nitro-4-trifluoromethyl-phenylazo)-6-(1-methyl-1-phenyl-ethyl)-4-(1,1,3,3-tetramethyl-butyl)-phenol

[0387] Following the procedure of Example 15, substituting heptane asthe solvent and using half the amount of sulfuric acid, the desiredmonoazo is obtained in a 68.4% yield based on phenol as determined bycalibrated HPLC analysis.

EXAMPLE 172-(2-nitro-4-trifluoromethyl-phenylazo)-6-(1-methyl-1-phenyl-ethyl)-4-(1,1,3,3-tetramethyl-butyl)-phenol

[0388] Following the procedure of Example 16, substituting hexane as thesolvent, the desired monoazo is obtained in a 73.1% yield based onphenol as determined by calibrated HPLC analysis.

EXAMPLE 182-(2-nitro-4-trifluoromethyl-phenylazo)-6-(1-methyl-1-phenyl-ethyl)-4-(1,1,3,3-tetramethyl-butyl)-phenol

[0389] Following the procedure of Example 16, substituting xylene as thesolvent, the desired monoazo is obtained in a 65.7% yield based onphenol as determined by calibrated HPLC analysis.

EXAMPLE 192-(2-nitro-4-trifluoromethyl-phenylazo)-6-(1-methyl-1-phenyl-ethyl)-4-(1,1,3,3-tetramethyl-butyl)-phenol

[0390] Following the procedure of Example 15, except eliminating thesulfuric acid precharge, the desired monoazo is obtained in a 76.3%yield based on phenol as determined by calibrated HPLC analysis.

EXAMPLE 202-(2-nitro-4-trifluoromethyl-phenylazo)-6-(1-methyl-1-phenyl-ethyl)-4-(1,1,3,3-tetramethyl-butyl)-phenol

[0391] Following the procedure of Example number 19, substitutingHostapur® SAS for the Petrosul® H-60 surfactant, the desired monoazo isobtained in a 71.7% yield based on phenol as determined by calibratedHPLC analysis.

EXAMPLE 212-(2-nitro-4-trifluoromethyl-phenylazo)-6-(1-methyl-1-phenyl-ethyl)-4-(1,1,3,3tetramethyl-butyl)-phenol

[0392] Following the procedure of Example 18, except using a phenol tonitroaniline ratio of 0.91 instead of 0.86, the desired monoazo isobtained in a 59.5% yield based on phenol as determined by calibratedHPLC analysis.

EXAMPLE 222-(2-nitro-4-trifluoromethyl-phenylazo)-6-(1-methyl-1-phenyl-ethyl)-4-(1,1,3,3-tetramethyl-butyl)-phenol

[0393] Following the procedure of Example 15, except using heptane asthe solvent, Hostapur® SAS as the surface active agent and adding 3 wt %2,6-lutidine, the desired monoazo is obtained in a 65% yield based on4-trifluoromethyl-2-nitroaniline as determined by calibrated HPLCanalysis.

EXAMPLE 232-(2-nitro-4-bromo-phenylazo)-6-(1-methyl-1phenyl-ethyl)-4-(1,1,3,3-tetramethyl-butyl)-phenol

[0394] Following the general procedure of Example 15 with heptane as thesolvent, the title compound is prepared as a crimson solid with amelting point of 117-120° C. ¹H-NMR (CDCl₃; 499.8494 MHz): δ0.83 (s,9H); δ1.44 (s, 6H); δ1.78 (s, 2H); δ1.79 (s, 6H); δ7.13-7.28 (multiplet,5H); δ7.62 (d, 1H); δ7.68 (d, 1H); δ7.79 (d, 1H); δ7.85 (d, 1H); δ8.19(d, 1H), δ12.94 (s, 1H). Elemental analysis: Calculated forC29H34BrN3O3: C 63.04; H 6.20; N 7.61. Found: C 62.76; H 6.01; N 7.28.

[0395] *4-Bromo-2-nitroaniline prepared as per Elder, J. W.; Paolillo,M. A. J. Chem. Ed. 1994, 71(6), A144.

EXAMPLE 242-(2-nitro-4-chloro-phenylazo)-6-(1-methyl-1-phenyl-ethyl)-4-(1,1,3,3-tetramethyl-butyl)-phenol

[0396] Following the general procedure of Example 22, the title compoundis prepared. Crystallization from xylene/methanol resulted in burgundycubic crystals with a melting point of 127-131° C.; elemental analysis:calculated for C29H34CIN3O3. C 68.56; H 6.75; N 8.27; Cl 6.98. Found: C68.67; H 6.81; N 8.28; Cl 6.99

EXAMPLE 252-(2,4-di-nitro-phenylazo)-6-(1-methyl-1-phenyl-ethyl)-4-(1,1,3,3-tetramethyl-butyl)-phenol

[0397] Following the general procedure of Example 22, the title compoundis prepared. Crystallization from xylene/methanol resulted in apurple-red, very fine needle-like solid with a melting point of 121-125°C. M.S.: a molecular ion of 518 in the positive ion mode is observedwith a fragmentation pattern consistent with the desired product. ¹H-NMR(CDCl₃; 499.8494 MHz): δ0.88 (s, 9H); δ1.40 (s, 6H); δ1.73 (s, 2H);δ1.76 (s, 6H); δ7.14-7.30 (multiplet, 5H); δ7.21 (d, 1H); δ7.51 (d, 1H);δ8.31 (d, 1H); δ8.47 (d, 1H); δ9.06 (d, 1H). Elemental analysis:Calculated for C29H34N4O5: C 67.16; H 6.61; N 10.80. Found C 67.09; H6.57; N 10.83.

EXAMPLE 26 2-(2-nitro-4-bromo-phenylazo)-4,6-di-tert-butyl phenol

[0398] Following the general procedure of instant Example 22, the titlecompound is prepared. Crystallization from xylene/methanol resulted inburgundy needle shaped crystals with a melting point of 188-190 ° C.M.S. a molecular ion of 433 in the positive ion mode with afragmentation pattern consistent with the desired structure is observed.¹H-NMR (CDCl₃; 499.8494 MHz): δ1.37 (s, 9H); δ1.46 (s, 9H); δ7.51 (d,1H); δ7.65 (d, 1H); δ7.84 (d, 1H); δ7.96 (d, 1H); δ8.25 (d, 1H); δ13.60(s, 1H). Elemental analysis calculated for C20H24BrN3O3: C 55.31; H5.57; N 9.67; Br 18.40. Found: C 55.22; H 5.57; N 9.69; Br 18.18.

EXAMPLE 272-[(4-bromo-2-nitrophenyl)azo]-6-tert-butyl-4-(2-carbomethoxyethyl)phenyl

[0399] Added 34.93 g (0.11 mol) of a 40% solution of nitrosylsulfuricacid in sulfuric acid to a rapidly stirred suspension of4-bromo-2-nitroaniline (23.87 g, 0.11 mol), methyl3-(3-tert-butyl-4-hydroxyphenyl)propionate (23.63 g, 0.10 mol),concentrated sulfuric acid (3.53 g, 0.036 mol), and Hostapur® SAS93 (1.0g) in heptane (100 g) and water (50 g) at 5° C. dropwise over 4 hours.The temperature of the reaction mixture is maintained between 2-5° C.during the addition of the nitrosylsulfuric acid. After the addition iscomplete, the reaction mixture is stirred at 4° C. for 15 minutes andthen allowed to warm to ambient temperature. The reaction mixture isstirred overnight at ambient temperature and the resultant precipitateis collected by filtration. The precipitate is washed with water (300mL) and the solid is dried in vacuo to produce 33.45 grams (72%) of amaroon solid. An analytical sample is prepared by recrystallization froma 1:1 mixture of meta-xylene and methanol (70 mL) to give 12.17 g offine maroon needles, mp 137 -139° C. ¹H NMR (CDCl₃)(499.8494 MHz) δ1.45(s, 9H), 2.69 (t, 2 H), 2.97 (t, 2 H), 3.71 (s, 3 H), 7.28 (d, 1 H),7.55 (d, 1 H), 7.84 (dd, 1 H), 7.91 (d, 1 H), 8.24 (d, 1 H), 13.40 (s, 1H), MS m/z 463, 465 (M⁺, M⁺+2). Calcd. for C₂₀H₂₂BrN₃O₅: C, 51.74; H,4.78; N, 9.05. Found: C, 50.33; H, 4.46; N, 9.44.

EXAMPLE 28

[0400] (a)6-Bromo-2-[3-tert-butyl-5-(2-carbomethoxyethyl)-2-hydroxyphenyl]-2H-benzotriazole-1-N-oxide

[0401] Hydrazine hydrate (1.98 g, 0.062) is added dropwise over 45minutes to a stirred mixture of2-[(4-bromo-2-nitrophenyl)azo]-6-tert-butyl-4-(2-carbomethoxyethyl)phenyl(11.13 g, 0.024 mol), 5% palladium on carbon (0.5 g), meta-xylene (50 g)and diethylamine (50 g) maintained at 6-8° C. When the addition iscomplete, the reaction mixture is allowed to warm slowly to roomtemperature. The reaction mixture is stirred at room temperature for 90minutes and the catalyst is removed by filtration. The volatiles areremoved in vacuo and the residue is recrystallized from methanol (50 mL)to give 7.82 grams (73%) of an orange solid. MS m/z 447, 449 (M⁺,correct isotope pattern Br); NMR (499.8494 MHz)(CDCl₃) δ1.48 (s, 9 H),2.66 (t, 2 H), 2.98 (t, 2 H), 3.70 (s, 3 H), 7.37 (d, 1 H), 7.42 (d, 1H), 7.61 (dd, 1 H), 7.75 (d, 1 H), 8.05(d, 1 H), 11.58 (s, 1 H).

[0402] (b)5-Bromo-2-[3-tert-butyl-5-(2-carbomethoxyethyl)-2-hydroxyphenyl]-2H-benzotriazole

[0403] Hydrazine hydrate (2.05 g, 0.064) is added dropwise over 115minutes to a stirred mixture of6-bromo-2-[3-tert-butyl-5-(2-carbomethoxyethyl)-2-hydroxyphenyl]-2H-benzotriazole-1-N-oxide(7.11 g, 0.016 mol), 5% palladium on carbon (0.5 g), meta-xylene (50 g)and diethylamine (50 g) at 55° C. After the slow addition of hydrazinehydrate is started, the reaction mixture is heated to reflux and held atreflux for 4 hours. The reaction mixture is filtered to remove catalystand the volatiles are removed in vacuo. Purify the residue by dry-columnflash chromatography (80:20 heptane: ethyl acetate eluent) andrecrystallization from methanol (35 mL) to give 3.02 grams (44%) of ayellow solid, mp 116-118° C. MS m/z 431, 433 (M⁺, correct isotopepattern Br); NMR (499.8494 MHz)(CDCl₃) δ1.50 (s, 9 H), 2.70 (t, 2 H),3.00 (t, 2 H 3.71 (s, 3 H), 7.23 (d, 1 H), 7.57 (dd, 1 H), 7.83 (d, 1H), 8.12 (d, 1 H), 8.13 (d, 1 H), 11.57 (s, 1 H).

EXAMPLE 292-(2-nitrophenylazo)-6-(1-methyl-1-phenyl-ethyl)-4-(1,1,3,3-tetramethyl-butyl)-phenol.

[0404] Following the general procedure of Example 29, the title compoundis prepared.

EXAMPLE 30

[0405] Following the general procedure of instant Example 15, thefollowing compounds are prepared:

[0406] 2-(2-nitrophenylazo) -4-(1,1,3,3-tetramethyl-butyl)-phenol;

[0407]2-(2-nitro-4-trifluoromethylphenylazo)-4-(1,1,3,3-tetramethyl-butyl)-phenol;

[0408] 2,4-bis(3-methyl-butyl)-6-(2-nitrophenylazo)-phenol;

[0409] 3-[3-tert-butyl-4-hydroxy-5-(2-nitro-phenylazo)-phenyl]-propionicacid methyl ester;

[0410] 2,4-bis(1-methyl-1-phenyl-ethyl)-6-(2-nitrophenylazo)-phenol;

[0411] 2,4-di-tert-butyl-6-(4-chloro-2-nitro-phenylazo)-4-methyl-phenol;and

[0412] 2,4-di-tert-butyl-6-(4-chloro-2-nitro-phenylazo)-phenol.

What is claimed is:
 1. A process for preparing a compound of formula (I)

which process comprises diazotizing a perfluoroalkyl substitutedo-nitroaniline of formula (II)

 using concentrated sulfuric acid and an alkali metal nitrite ornitrosylsulfuric acid to form the corresponding diazonium salt offormula (III)

coupling said diazonium salt with a phenol of formula (IV)

 to form a monoazobenzene compound of formula (V)

reducing the monoazobenzene intermediate of formula (V) to thecorresponding 2H-benzotriazole compound of formula (I) by conventionalreduction means; wherein G₁ is hydrogen or chloro, G₂ is perfluoroalkylof 1 to 12 carbon atoms, E₁ is hydrogen, straight or branched chainalkyl of 1 to 24 carbon atoms, straight or branched chain alkenyl of 2to 24 carbon atoms, cycloalkyl of 5 to 12 carbon atoms, phenylalkyl of 7to 15 carbon atoms, phenyl, or said phenyl or said phenylalkylsubstituted on the phenyl ring by one to three alkyl of 1 to 4 carbonatoms; or E₁ is alkyl of 1 to 24 carbon atoms substituted by one or twohydroxy groups, E₂ is straight or branched alkyl chain of 1 to 24 carbonatoms, straight or branched chain alkenyl of 2 to 18 carbon atoms,cycloalkyl of 5 to 12 carbon atoms, phenylalkyl of 7 to 15 carbon atoms,phenyl, or said phenyl or said phenylalkyl substituted on the phenylring by one to three alkyl of 1 to 4 carbon atoms; or E₂ is said alkylof 1 to 24 carbon atoms or said alkenyl of 2 to 18 carbon atomssubstituted by one or more —OH, —OCOE₁₁, —OE₄, —NCO, —NHCOE₁₁ or —NE₇E₈,or mixtures thereof, where E₄ is straight or branched chain alkyl of 1to 24 carbon atoms or alkenyl of 2 to 18 carbon atoms; or said alkyl orsaid alkenyl interrupted by one or more —O—, —NH— or —NE₄— groups ormixtures thereof and which can be unsubstituted or substituted by one ormore —OH, —OE₄ or —NH₂ groups or mixtures thereof; or E₂ is—(CH₂)_(m)—CO—E₅; E₅ is OE₆ or NE₇E₈, or E₅ is —PO(OE₁₂)₂, —OSi(E₁₁)₃ or—OCO—E₁₁, or straight or branched chain C₁-C₂₄alkyl which can beinterrupted by —O—, —S— or —NE₁₁ and which can be unsubstituted orsubstituted by —OH or —OCO—E₁₁, C₅-C₁₂ cycloalkyl which is unsubstitutedor substituted by —OH, straight chain or branched C₂-C₁₈alkenyl which isunsubstituted or substituted by —OH, C₇-C₁₅aralkyl, —CH₂—CHOH—E₁₃ orglycidyl, E₆ is hydrogen, straight or branched chain C₁-C₂₄alkyl whichis unsubstituted or substituted by one or more OH, OE₄ or NH₂ groups, or—OE₆ is —(OCH₂CH₂)_(w)OH or —(OCH₂CH₂)_(w)OE₂₁ where w is 1 to 12 andE₂₁ is alkyl of 1 to 12 carbon atoms, E₇ and E₈ are independentlyhydrogen, alkyl of 1 to 18 carbon atoms, straight or branched chainalkenyl of 2 to 18 carbon atoms, straight or branched chain C₃-C₁₈alkylwhich is interrupted by —O—, —S— or —NE₁₁—, C₅-C₁₂cycloalkyl, C₆-C₁₄arylor C₁-C₃hydroxylalkyl, or E₇ and E₈ together with the N atom are apyrrolidine, piperidine, piperazine or morpholine ring, or E₅ is—X—(Z)_(p)—Y—E₁₅ wherein X is —O— or —N(E₁₆)—, Y is —O— or —N(E₁₇)—, Zis C₂-C₁₂-alkylene, C₄-C₁₂-alkylene interrupted by one to three nitrogenatoms, oxygen atoms or a mixture thereof, or is C₃-C₁₂-alkylene,butenylene, butynylene, cyclohexylene or phenylene, each substituted bya hydroxyl group, m is zero, 1 or 2, p is 1, or p is also zero when Xand Y are —N(E₁₆)— and —N(E₁₇)—, respectively, E₁₅ is a group—CO—C(E₁₈)═C(H)E₁₉ or, when Y is —N(E₁₇)—, forms together with E₁₇ agroup —CO—CH═CH—CO—, wherein E₁₈ is hydrogen or methyl, and E₁₉ ishydrogen, methyl or —CO—X—E₂₀, wherein E₂₀ is hydrogen, C₁-C₁₂-alkyl ora group of the formula

 wherein the symbols E₁, G₂, X, Z, m and p have the meanings definedabove, and E₁₆ and E₁₇ independently of one another are hydrogen,C₁-C₁₂-alkyl, C₃-C₁₂-alkyl interrupted by 1 to 3 oxygen atoms, or iscyclohexyl or C₇-C₁₅aralkyl, and E₁₆ together with E₁₇ in the case whereZ is ethylene, also forms ethylene, E₁₁ is hydrogen, straight orbranched chain C₁-C₁₈alkyl, C₅-C₁₂cycloalkyl, straight or branched chainC₂-C₁₈alkenyl, C₆-C₁₄aryl or C₇-C₁₅aralkyl, E₁₂ is straight or branchedchain C₁-C₁₈alkyl, straight or branched chain C₃-C₁₈alkenyl,C₅-C₁₀cycloalkyl, C₆-C₁₆aryl or C₇-C₁₅aralkyl, and E₁₃ is H, straightchain or branched C₁-C₁₈alkyl which is substituted by —PO(OE₁₂)₂, phenylwhich is unsubstituted or substituted by OH, C₇-C₁₅aralkyl or —CH₂OE₁₂,with the proviso that when concentrated sulfuric acid and alkali metalnitrite are used, E₁ and E₂ are alkyl of 1 to 4 carbon atoms, or E₁ canalso be hydrogen.
 2. A process according to claim 1 wherein the alkalimetal nitrite is sodium nitrite.
 3. A process according to claim 1wherein nitrosylsulfuric acid is used to diazotize the o-nitroanilinecompound of formula (II).
 4. A process according to claim 1 for thepreparation of a compound of formula (Ia)

which process comprises diazotizing a substituted o-nitroanilinecompound of formula (IIa)

 using concentrated sulfuric acid and sodium nitrite or nitrosylsulfuricacid to form the diazonium salt of formula (IIIa)

coupling said diazonium salt with a phenol of formula (IVa)

 to form the corresponding monoazobenzene compound of formula (Va)

reducing the monoazobenzene intermediate of formula (Va) to thecorresponding 2H-benzotriazole compound of formula (Ia) by conventionalreduction means; with the proviso that when concentrated sulfuric acidand alkali metal nitrite are used, E₁ and E₂ are alkyl of 1 to 4 carbonatoms, or E₁ can also be hydrogen.
 5. A process according to claim 1where in the compound of formula (I) G₁ is hydrogen, G₂ is —CF₃, E₁ isphenylalkyl of 7 to 15 carbon atoms, phenyl, or said phenyl or saidphenylalkyl substituted on the phenyl ring by one to three alkyl of 1 to4 carbon atoms, E₂ is straight or branched alkyl chain of 1 to 24 carbonatoms, straight or branched chain alkenyl of 2 to 18 carbon atoms,cycloalkyl of 5 to 12 carbon atoms, phenylalkyl of 7 to 15 carbon atoms,phenyl, or said phenyl or said phenylalkyl substituted on the phenylring by one to three alkyl of 1 to 4 carbon atoms; or E₂ is said alkylof 1 to 24 carbon atoms or said alkenyl of 2 to 18 carbon atomssubstituted by one or more —OH, —OCOE₁₁, —OE₄, —NCO, —NH₂, —NHCOE₁₁,—NHE₄ or —N(E₄)₂, or mixtures thereof, where E₄ is straight or branchedchain alkyl of 1 to 24 carbon atoms; or said alkyl or said alkenylinterrupted by one or more —O—, —NH— or —NE₄— groups or mixtures thereofand which can be unsubstituted or substituted by one or more —OH, —OE₄or —NH₂ groups or mixtures thereof; or where in the compound of formula(I) G₁ is hydrogen, G₂ is —CF₃, E₁ is hydrogen or straight or branchedalkyl of 4 to 24 carbon atoms, and E₂ is as defined above.
 6. A processaccording to claim 1 where in the compound of formula (I) G₁ ishydrogen, G₂ is —CF₃, E₁ is hydrogen, straight or branched alkyl of 4 to24 carbon atoms or phenylalkyl of 7 to 15 carbon atoms, E₂ is—(CH₂)_(m)—CO—E₅, E₅ is —OE₆ or —NE₇E₈, or E₅ is —X—(Z)_(p)—Y—E₁₅wherein X is —O— or —N(E₁₆)—, Y is —O— or —N(E₁₇)—, Z isC₂-C₁₂-alkylene, C₄-C₁₂-alkylene interrupted by one to three nitrogenatoms, oxygen atoms or a mixture thereof, or is C₃-C₁₂-alkylene,butenylene, butynylene, cyclohexylene or phenylene, each substituted bya hydroxyl group, m is 0, 1, 2 or 3, p is 1 or p is also zero when X andY are —N(E₁₆)— and —N(E₁₇)—, respectively, E₁₅ is a group—CO—C(E₁₈)═C(H)E₁₉ or, when Y is —N(E₁₇)—, forms together with E₁₇ agroup —CO—CH═CH—CO—, wherein E₁₈ is hydrogen or methyl, and E₁₉ ishydrogen, methyl or —CO—X—E₂₀, wherein E₂₀ is hydrogen, C₁-C₁₂-alkyl ora group of the formula


7. A process according to claim 1 where in the compound of formula (I)G₁ is hydrogen, G₂ is —CF₃, E₁ is phenylalkyl of 7 to 15 carbon atoms,phenyl, or said phenyl or said phenylalkyl substituted on the phenylring by one to three alkyl of 1 to 4 carbon atoms, E₂ is straight orbranched alkyl chain of 1 to 24 carbon atoms, straight or branched chainalkenyl of 2 to 18 carbon atoms, cycloalkyl of 5 to 12 carbon atoms,phenylalkyl of 7 to 15 carbon atoms, phenyl, or said phenyl or saidphenylalkyl substituted on the phenyl ring by one to three alkyl of 1 to4 carbon atoms; or E₂ is said alkyl of 1 to 24 carbon atoms or saidalkenyl of 2 to 18 carbon atoms substituted by one or more —OH, —OCOE₁₁,—NH₂ or —NHCOE₁₁, or mixtures thereof, or said alkyl or said alkenylinterrupted by one or more —O— and which can be unsubstituted orsubstituted by one or more —OH, or where in the compound of formula (I)G₁ is hydrogen, G₂ is —CF₃, E₁ is hydrogen, straight or branched alkylof 4 to 24 carbon atoms or phenylalkyl of 7 to 15 carbon atoms, and E₂is as defined above.
 8. A process according to claim 1 where in thecompound of formula (I) G₁ is hydrogen, G₂ is —CF₃, E₁ is hydrogen,straight or branched alkyl of 4 to 24 carbon atoms or phenylalkyl of 7to 15 carbon atoms, E₂ is —(CH₂)_(m)—CO—E₅, E₅ is —OE₆ or —NE₇E₈ whereE₆ is hydrogen, straight or branched chain C₁-C₂₄alkyl which isunsubstituted or substituted by one or more OH groups, or —OE₆ is—(OCH₂CH₂)_(w)OH or —(OCH₂CH₂)_(w)OE₂₁ where w is 1to 12 and E₂₁ isalkyl of 1 to 12 carbon atoms, and E₇ and E₈ are independently hydrogen,alkyl of 1 to 18 carbon atoms, straight or branched chain C₃-C₁₈alkylwhich is interrupted by —O—, —S— or —NE₁₁—, C₅-C₁₂cycloalkyl, C₆-C₁₄arylor C₁-C₃hydroxylalkyl, or E₇ and E₈ together with the N atom are apyrrolidine, piperidine, piperazine or morpholine ring.
 9. A processaccording to claim 1 wherein the compound of formula (I) is (a)5-trifluoromethyl-2-(2-hydroxy-3-α-cumyl-5-tert-octylphenyl)-2H-benzotriazole;(b) 5-trifluoromethyl-2-(2-hydroxy-5-tert-octylphenyl)-2H-benzotriazole;(c)5-trifluoromethyl-2-(2-hydroxy-3,5-di-tert-octylphenyl)-2H-benzotriazole;(d)5-trifluoromethyl-2-[2-hydroxy-5-(2-hydroxyethyl)phenyl]-2H-benzotriazole;(e)5-trifluoromethyl-2-(2-hydroxy-3,5-di-α-cumylphenyl)-2H-benzotriazole;(f)3-(5trifluoromethyl-2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyhydrocinnamicacid; (g) methyl 3-(5-trifluoromethyl-2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyhydrocinnamate; (h) isooctyl3-(5-trifluoromethyl-2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyhydrocinnamate;(i)5-trifluoromethyl-2-[2-hydroxy-5-(3-hydroxypropyl)phenyl]-2H-benzotriazole;(j)5-trifluoromethyl-2-[2-hydroxy-5-(3-acryloyloxypropyl)phenyl]-2H-benzotriazole;(k)5-trifluoromethyl-2-[2-hydroxy-5-(3-methacryloyloxpropyl)phenyl]-2H-benzotriazole;(l)5-trifluoromethyl-2-[2-hydroxy-5-(3-acrylylaminopropyl)phenyl]-2H-benzotriazole;(m)5-trifluoromethyl-2-[2-hydroxy-5-(3-methacrylylaminopropyl)phenyl]-2H-benzotriazole;(n)5-trifluoromethyl-2-(2-hydroxy-3-α-cumyl-5-tert-butylphenyl)-2H-benzotriazole;(o)5-trifluoromethyl-2-(2-hydroxy-3-α-cumyl-5-nonylphenyl)-2H-benzotriazole;(p)5-trifluoromethyl-2-[2-hydroxy-3-α-cumyl-5-(2-hydroxyethyl)phenyl]-2H-benzotriazole;(q)5-trifluoromethyl-2-[2-hydroxy-3-α-cumyl-5-(3-hydroxypropyl)phenyl]-2H-benzotriazole;(r)5-trifluoromethyl-2-(2-hydroxy-3,5-ditert-amylphenyl)-2H-benzotriazole;(s)5-trifluoromethyl-2-(2-hydroxy-3,5-ditert-butylphenyl)-2H-benzotriazole;(t)5-trifluoromethyl-2-(2-hydroxy-3-dodecyl-5-methylphenyl)-2H-benzotriazole;(u)5-trifluoromethyl-2-[2-hydroxy-3-tert-butyl-5-(3-hydroxypropyl)phenyl)-2H-benzotriazole;or (v)5-trifluoromethyl-2-[2-hydroxy-3-tert-butyl-5-(2-hydroxyethyl)phenyl]-2H-benzotriazole.10. A process according to claim 1 for the preparation of a compound offormula (Ib)

which process comprises diazotizing a substituted o-nitroanilinecompound of formula (IIa)

 using nitrosylsulfuric acid to form the diazonium salt of formula(IIIa)

coupling said diazonium salt with a phenol of formula (IVb)

 to form the corresponding monoazobenzene compound of formula (Vb)

reducing the monoazobenzene intermediate of formula (Vb) to thecorresponding 2H-benzotriazole compound of formula (Ib) by conventionalreduction means.
 11. A process according to claim 1 for the preparationof a compound of formula (Ic)

which process comprises diazotizing a substituted o-nitroanilinecompound of formula (IIa)

 using nitrosylsulfuric acid to form the diazonium salt of formula(IIIa)

coupling said diazonium salt with a phenol of formula (IVc)

 to form the corresponding monoazobenzene compound of formula (Vc)

reducing the monoazobenzene intermediate of formula (Vc) to thecorresponding 2H-benzotriazole compound of formula (Ic) by conventionalreduction means.
 12. A process according to claim 1 where in the processfor making the diazonium salts using a perfluoroalkyl substitutedo-nitroaniline (i.e. 4-trifluoromethyl-2-nitroaniline, CF₃-ONA),sulfuric acid and an aqueous alkali metal nitrite solution, a. the molarratio of CF₃-ONA:sulfuric acid is 1:10 to 1:1; b. the molar ratio ofCF₃-ONA:sodium nitrite is 1:1 to 1:4; and c. the temperature used forthis reaction is from −30° C. to 50° C.
 13. A process according to claim12 wherein a. the molar ratio of CF₃-ONA:sulfuric acid is 1:5 to 1:1; b.the molar ratio of CF₃-ONA:sodium nitrite is 1:1 to 1:2; and c. thetemperature used for this reaction is from −20° C. to 20° C.
 14. Aprocess according to claim 13 wherein a. the molar ratio ofCF₃-ONA:sulfuric acid is 1:2-3.5; b. the molar ratio of CF₃-ONA:sodiumnitrite is 1:1; and c. the temperature used for this reaction is from−10° C. to 5° C.
 15. A process according to claim 1 where in the processfor making the diazonium salts using a perfluoroalkyl substitutedo-nitroaniline (i.e. 4-trifluoromethyl-2-nitroaniline, CF₃-ONA) andnitrosylsulfuric acid, a. the molar ratio of CF₃-ONA:nitrosylsulfuricacid is 1:1 to 1:2; b. the molar ratio of CF₃-ONA:sulfuric acid is 1:1to 1:10, and c. the temperature used for this reaction is from −30° C.to 50° C.
 16. A process according to claim 15 wherein a. the molar ratioof CF₃-ONA:nitrosylsulfuric acid is 1:1 to 1:1.2; b. the molar ratio ofCF₃-ONA:sulfuric acid is 1:2 to 1:7; and c. the temperature used forthis reaction is from −20° C. to 40° C.
 17. A process according to claim16 wherein a. the molar ratio of CF₃-ONA:nitrosylsulfuric acid is 1:1;b. the molar ratio of CF₃-ONA:sulfuric acid is 1:2 to 1:5.; and c. thetemperature used for this reaction is from 0° C. to 25° C.
 18. A processaccording to claim 1 wherein the monoazobenzene intermediate of formula(V) is prepared in a solvent containing a surface active modifier at atemperature of −30° C. to 75° C.
 19. A process according to claim 18wherein the temperature is −20° C. to 50° C.
 20. A process according toclaim 19 wherein the temperature is −10° C. to 35° C.
 21. A processaccording to claim 18 wherein the solvent is water, an aromatichydrocarbon, an aliphatic hydrocarbon or a mixture thereof.
 22. Aprocess according to claim 21 wherein the solvent is water, toluene,o-xylene, m-xylene, p-xylene, a mixture of said xylenes, mesitylene,pseudocumene, hexane, heptane, octane, nonane or a mixture thereof. 23.A process according to claim 22 wherein the solvent is water, toluene,o-xylene, m-xylene, p-xylene, a mixture of said xylenes, heptane or amixture thereof.
 24. A process according to claim 18 wherein the surfaceactive modifier is selected from the group consisting of emulsifyingagents, surfactants, phase transfer agents and dispersants.
 25. Aprocess according to claim 24 wherein the surface active modifier isHOSTAPUR® SAS93 (Hoechst) or PETROSUL® M-60 (Penreco).
 26. A processaccording to claim 1 wherein the molar ratio of diazonium salt:phenol is2:1 to 1:2.
 27. A process according to claim 26 wherein the molar ratioof diazonium salt:phenol is 1.5:1 to 1:1.5.
 28. A process according toclaim 27 wherein the molar ratio of diazonium salt:phenol is 1:1.
 29. Aprocess for the preparation of 2-(2-nitrophenylazo) substituted phenolsof the formula (VI)

which process comprises combining an ortho-nitroaniline of formula (VII)

a phenol of formula (VIII)

a nitrosating agent together in a multiphase reaction medium andreacting the mixture for a sufficient time without isolation ofintermediate products, wherein the multiphase medium comprises anorganic and an aqueous phase and optionally a surface active agent;wherein G₁ is hydrogen or chloro, G₂ is perfluoroalkyl (C_(n)F_(2n+1))where n is equal to 1-12, hydrogen, halogen, NO₂, cyano, R₃S—, R₃SO—,R₃SO₂—, phenyl, naphthyl, biphenylyl, 9-phenanthryl or said phenyl,naphthyl, biphenylyl or 9-phenanthryl substituted by one to three alkylof 1 to 18 carbon atoms, phenylalkyl of 7 to 15 carbon atoms, R₃S—,R₃SO—, R₃SO₂, aryl of 6 to 10 carbon atoms, perfluoroalkyl of 1 to 12carbon atoms, halogen, nitro, cyano, carboxyl, alkoxycarbonyl of 2 to 19carbon atoms, hydroxyl, alkoxy of 1 to 18 carbon atoms, aryloxy of 6 to10 carbon atoms, aralkoxy of 7 to 15 carbon atoms, vinyl, acetyl,acetamido, amino, dialkylamino of 2 to 12 carbon atoms, formyl,thioalkoxy of 1 to 18 carbon atoms, hydroxymethyl, aminomethyl,halomethyl, sulfato, phosphato or where any two substituents form abenzo ring with the aryl moiety to which they are attached, R₁ ishydrogen, straight or branched chain alkyl of 1 to 24 carbon atoms,straight or branched chain alkenyl of 2 to 24 carbon atoms, cycloalkylof 5 to 12 carbon atoms, phenylalkyl of 7 to 15 carbon atoms, phenyl, orsaid phenyl or said phenylalkyl substituted on the phenyl ring by one tothree alkyl of 1 to 4 carbon atoms; or R₁ is alkyl of 1 to 24 carbonatoms substituted by one or two hydroxy groups, R₂ is straight orbranched alkyl chain of 1 to 24 carbon atoms, straight or branched chainalkenyl of 2 to 18 carbon atoms, cycloalkyl of 5 to 12 carbon atoms,phenylalkyl of 7 to 15 carbon atoms, phenyl, or said phenyl or saidphenylalkyl substituted on the phenyl ring by one to three alkyl of 1 to4 carbon atoms; or R₂ is said alkyl of 1 to 24 carbon atoms or saidalkenyl of 2 to 18 carbon atoms substituted by one or more —OH, —OCOE₁₁,—OE₄, —NCO, —NHCOE₁₁ or —NE₇E₈, or mixtures thereof, where E₄ isstraight or branched chain alkyl of 1 to 24 carbon atoms; alkenyl of 2to 18 carbon atoms; or said alkyl or said alkenyl interrupted by one ormore —O—, —NH— or —NE₄— groups or mixtures thereof and which can beunsubstituted or substituted by one or more —OH, —OE₄ or —NH₂ groups ormixtures thereof; or R₂ is —(CH₂)_(m)—CO—E₅; R₃ is alkyl of 1 to 20carbon atoms, hydroxyalkyl of 2 to 20 carbon atoms, alkenyl of 3 to 18carbon atoms, cycloalkyl of 5 to 12 carbon atoms, phenylalkyl of 7 to 15carbon atoms, aryl of 6 to 10 carbon atoms or said aryl substituted byone or two alkyl of 1 to 4 carbon atoms; E₅ is OE₆ or NE₇E₈, or E₆ is—PO(OE₁₂)₂, —OSi(E₁₁)₃ or —OCO—E₁₁ or straight or branched chainC₁-C₂₄alkyl which can be interrupted by —O—, —S— or —NE₁₁ and which canbe unsubstituted or substituted by —OH or —OCO—E₁₁, C₅-C₁₂ cycloalkylwhich is unsubstituted or substituted by —OH, straight chain or branchedC₂-C₁₈alkenyl which is unsubstituted or substituted by —OH,C₇-C₁₅aralkyl, —CH₂—CHOH—E₁₃ or glycidyl, E₆ is hydrogen, straight orbranched chain C₁-C₂₄alkyl which is unsubstituted or substituted by oneor more OH, OE₄ or NH₂ groups, or —OE₆ is —(OCH₂CH₂)_(w)OH or—(OCH₂CH₂)_(w)OE₂₁ where w is 1 to 12 and E₂₁ is alkyl of 1 to 12 carbonatoms, E₇ and E₈ are independently hydrogen, alkyl of 1 to 18 carbonatoms, straight or branched chain alkenyl of 2 to 18 carbon atoms,straight or branched chain C₃-C₁₈alkyl which is interrupted by —O—, —S—or —NE₁₁—, C₅-C₁₂cycloalkyl, C₆-C₁₄aryl or C₁-C₃hydroxylalkyl, or E₇ andE₈ together with the N atom are a pyrrolidine, piperidine, piperazine ormorpholine ring, or E₅ is —X—(Z)_(p)—Y—E₁₅ wherein X is —O— or —N(E₁₆)—,Y is —O— or —N(E₁₇)—, Z is C₂-C₁₂-alkylene, C₄-C₁₂-alkylene interruptedby one to three nitrogen atoms, oxygen atoms or a mixture thereof, or isC₃-C₁₂-alkylene, butenylene, butynylene, cyclohexylene or phenylene,each substituted by a hydroxyl group, m is zero, 1 or 2, p is 1, or p isalso zero when X and Y are —N(E₁₆)— and —N(E₁₇)—, respectively, E₁₅ is agroup —CO—C(E₁₈)═C(H)E₁₉ or, when Y is —N(E₁₇)—, forms together with E₁₇a group —CO—CH═CH—CO—, wherein E₁₈ is hydrogen or methyl, and E₁₉ ishydrogen, methyl or —CO—X—E₂₀, wherein E₂₀ is hydrogen, C₁-C₁₂-alkyl,and E₁₆ and E₁₇ independently of one another are hydrogen, C₁-C₁₂-alkyl,C₃-C₁₂-alkyl interrupted by 1 to 3 oxygen atoms, or is cyclohexyl orC₇-C₁₅aralkyl, and E₁₆ together with E₁₇ in the case where Z isethylene, also forms ethylene, E₁₁ is hydrogen, straight or branchedchain C₁-C₁₈alkyl, C₅-C₁₂cycloalkyl, straight or branched chainC₂-C₁₈alkenyl, C₆-C₁₄aryl or C₇-C₁₅aralkyl, E₁₂ is straight or branchedchain C₁-C₁₈alkyl, straight or branched chain C₃-C₁₈alkenyl,C₅-C₁₀cycloalkyl, C₆-C₁₆aryl or C₇-C₁₅aralkyl, and E₁₃ is H, straightchain or branched C₁-C₁₈alkyl which is substituted by —PO(OE₁₂)₂, phenylwhich is unsubstituted or substituted by OH, C₇-C₁₅aralkyl or —CH₂OE₁₂.30. A process according to claim 29 wherein G₁ is hydrogen, G₂ is —CF₃,halogen or hydrogen, R₁ is phenylalkyl of 7 to 15 carbon atoms, phenyl,or said phenyl or said phenylalkyl substituted on the phenyl ring by oneto three alkyl of 1 to 4 carbon atoms, R₂ is straight or branched alkylchain of 1 to 24 carbon atoms, straight or branched chain alkenyl of 2to 18 carbon atoms, cycloalkyl of 5 to 12 carbon atoms, phenylalkyl of 7to 15 carbon atoms, phenyl, or said phenyl or said phenylalkylsubstituted on the phenyl ring by one to three alkyl of 1 to 4 carbonatoms; or E₂ is said alkyl of 1 to 24 carbon atoms or said alkenyl of 2to 18 carbon atoms substituted by one or more —OH, —OCOE₁₁, —OE₄, —NCO,—NH₂, —NHCOE₁₁, —NHE₄ or —N(E₄)₂, or mixtures thereof, where E₄ isstraight or branched chain alkyl of 1 to 24 carbon atoms; or said alkylor said alkenyl interrupted by one or more —O—, —NH— or —NE₄— groups ormixtures thereof and which can be unsubstituted or substituted by one ormore —OH, —OE₄ or —NH₂ groups or mixtures thereof.
 31. A processaccording to claim 29 wherein, G₁ is hydrogen, G₂ is —CF₃, halogen orhydrogen, R₁ is hydrogen or straight or branched alkyl of 4 to 24 carbonatoms.
 32. A process according to claim 29 wherein G₁ is hydrogen, G₂ is—CF₃, chloro, fluoro or bromo, R₁ is hydrogen, straight or branchedalkyl of 4 to 24 carbon atoms or phenylalkyl of 7 to 15 carbon atoms, R₂is —(CH₂)_(m)—CO—E₅, E₅ is —OE₆ or —NE₇E₈, or E₅ is —X—(Z)_(p)—Y—E₁₅wherein X is —O— or —N(E₁₆)—, Y is —O— or —N(E₁₇)—, Z isC₂-C₁₂-alkylene, C₄-C₁₂-alkylene interrupted by one to three nitrogenatoms, oxygen atoms or a mixture thereof, or is C₃-C₁₂-alkylene,butenylene, butynylene, cyclohexylene or phenylene, each substituted bya hydroxyl group, m is 0, 1, 2 or 3, p is 1, or p is also zero when Xand Y are —N(E₁₆)— and —N(E₁₇)—, respectively, E₁₅ is a group—CO—C(E₁₈)═C(H)E₁₉ or, when Y is —N(E₁₇)—, forms together with E₁₇ agroup —CO—CH═CH—CO—, wherein E₁₈ is hydrogen or methyl, and E₁₉ ishydrogen, methyl or —CO—X—E₂₀, wherein E₂₀ is hydrogen, C₁-C₁₂-alkyl.33. A process according to claim 29 wherein G₁ is hydrogen, G₂ is —CF₃,R₁ is phenylalkyl of 7 to 15 carbon atoms, phenyl, or said phenyl orsaid phenylalkyl substituted on the phenyl ring by one to three alkyl of1 to 4 carbon atoms, R₂ is straight or branched alkyl chain of 1 to 24carbon atoms, straight or branched chain alkenyl of 2 to 18 carbonatoms, cycloalkyl of 5 to 12 carbon atoms, phenylalkyl of 7 to 15 carbonatoms, phenyl, or said phenyl or said phenylalkyl substituted on thephenyl ring by one to three alkyl of 1 to 4 carbon atoms; or E₂ is saidalkyl of 1 to 24 carbon atoms or said alkenyl of 2 to 18 carbon atomssubstituted by one or more —OH, —OCOE₁₁, —NH₂ or —NHCOE₁₁, or mixturesthereof, or said alkyl or said alkenyl interrupted by one or more —O—and which can be unsubstituted or substituted by one or more —OH.
 34. Aprocess according to claim 29 wherein, G₁ is hydrogen, G₂ is —CF₃, R₁ ishydrogen, straight or branched alkyl of 4 to 24 carbon atoms orphenylalkyl of 7 to 15 carbon atoms.
 35. A process according to claim 29wherein G₁ is hydrogen, G₂ is —CF₃, R₁ is hydrogen, straight or branchedalkyl of 4 to 24 carbon atoms or phenylalkyl of 7 to 15 carbon atoms, R₂is —(CH₂)_(m)—CO—E₅, E₅ is —OE₆ or —NE₇E₈ where E₆ is hydrogen, straightor branched chain C₁-C₂₄alkyl which is unsubstituted or substituted byone or more OH groups, or —OE₆ is —(OCH₂CH₂)_(w)OH or —(OCH₂CH₂)_(w)OE₂₁where w is 1 to 12 and E₂₁ is alkyl of 1 to 12 carbon atoms, and E₇ andE₈ are independently hydrogen, alkyl of 1 to 18 carbon atoms, straightor branched chain C₃-C₁₈alkyl which is interrupted by —O—, —S— or—NE₁₁—, C₅-C₁₂cycloalkyl, C₆-C₁₄aryl or C₁-C₃hydroxylalkyl, or E₇ and E₈together with the N atom are a pyrrolidine, piperidine, piperazine ormorpholine ring.
 36. A process according to claim 29 wherein thenitrosating agent is nitrosylsulfuric acid in a sulfuric acid.
 37. Aprocess according to claim 36 wherein the molar ratio of nitroaniline tonitrosylsulfuric acid is 1:1 to 1:2.
 38. A process according to claim 37wherein the molar ratio of nitroaniline to nitrosylsulfuric acid is 1:1to 1:1.2.
 39. A process according to claim 38 wherein the molar ratio ofnitroaniline to nitrosylsulfuric acid is 1:1.
 40. A process according toclaim 29 for the preparation of a compound of formula (VIa)

which process comprises combining an ortho-nitroaniline compound offormula (VIIa)

a phenol of formula (VIIIa)

a nitrosating agent selected from concentrated sulfuric acid solutionand sodium nitrite or nitrosylsulfuric acid, together in a two phasereaction medium comprising an organic and an aqueous phase and a surfaceactive agent and reacting the mixture for a sufficient time withoutisolation of intermediate products.
 41. A process according to claim 40for the preparation of a compound of formula (VIb)

which process comprises combining an ortho-nitroaniline compound offormula (VIIb)

a phenol of formula (VIIIb)

nitrosylsulfuric acid in sulfuric acid together in a two phase reactionmedium comprising an organic and an aqueous phase and a surface activeagent and reacting the mixture for a sufficient time without isolationof intermediate products; wherein G₂ is CF₃, hydrogen, fluorine,chlorine or bromine.
 42. A process according to claim 36, wherein thenitroaniline to sulfuric acid ratio is 1:1 to 1:10.
 43. A processaccording to claim 42 wherein the nitroaniline to sulfuric acid ratio is1:2 to 1:7.
 44. A process according to claim 43 wherein the nitroanilineto sulfuric acid ratio is 1:2 to 1:5.
 45. A process according to claim29 further comprising converting the resulting 2-(2-nitrophenylazo)substituted phenols of formula (VI) to a corresponding 2H-benzotriazolecompound.
 46. A process according to claim 40 for the preparation of acompound of formula (VIc)

which process comprises combining an ortho-nitroaniline compound offormula (VIIc)

a phenol of formula (VIIIc)

nitrosylsulfuric acid in the form of an acid solution, together in a twophase reaction medium comprising an organic and an aqueous phase and asurface active agent and reacting the mixture for a sufficient timewithout isolation of intermediate products.
 47. A process according toclaim 36, wherein the temperature used is from −30° C. to 50° C.
 48. Aprocess according to claim 47 wherein the temperature used is from −20°C. to 40° C.
 49. A process according to claim 48 wherein the temperatureused is from 0° C. to 25° C.
 50. A process according to claim 29 whereinthe nitrosating reagent is sulfuric acid and an alkali metal nitrite.51. A process according to claim 50 wherein the alkali metal nitrite issodium nitrite.
 52. A process according to claim 50 wherein thenitroaniline to sulfuric acid ratio is 1:10 to 1:1.
 53. A processaccording to claim 52 wherein the nitroaniline to sulfuric acid ratio is1:5 to 1:1.
 54. A process according to claim 53 wherein the nitroanilineto sulfuric acid ratio is 1:2 to 1:3.5.
 55. A process according to claim51 wherein the nitroaniline to sodium nitrite ratio is 1:1 to 1:4.
 56. Aprocess according to claim 55 wherein the nitroaniline to sodium nitriteratio is 1:1 to 1:2.
 57. A process according to claim 56 wherein thenitroaniline to sodium nitrite ratio is 1:1.
 58. A process according toclaim 50, wherein the temperature used is from −30°C. to 50° C.
 59. Aprocess according to claim 58 wherein the temperature used is from −20°C. to 20° C.
 60. A process according to claim 59 wherein the temperatureused is from −10° C. to 5° C.
 61. A process according to claim 29wherein the ratio of nitroaniline to phenol is from 2:1 to 1:2.
 62. Aprocess according to claim 61 wherein the ratio of nitroaniline tophenol is from 1.5:1 to 1:1.5.
 63. A process according to claim 62wherein the ratio of nitroaniline to phenol is from 1:1 to 1:0.85.
 64. Aprocess according to claim 29 wherein the process is carried out in thepresence of a surface active agent.
 65. A process according to claim 64wherein the surface active agent is selected from the group consistingof secondary alkane sulfonates and petroleum sulphonate salts.
 66. Aprocess according to claim 29 wherein the organic medium comprises asolvent selected from aromatic hydrocarbons, aliphatic hydrocarbons or amixture thereof.
 67. A process according to claim 66 wherein the solventis ligroine, toluene, o-xylene, m-xylene, p-xylene or a mixture of saidxylenes, mesitylene, psuedocumene, hexane, heptane, octane, nonane, or amixture thereof.
 68. A process according to claim 67 wherein the solventis ligroine, toluene, o-xylene, m-xylene, p-xylene or a mixture of saidxylenes, heptane or a mixture thereof.